diff --git a/server/src/game-implementations/games/_common.ts b/server/src/game-implementations/games/_common.ts
index 523a6ecc1..c5396bd22 100644
--- a/server/src/game-implementations/games/_common.ts
+++ b/server/src/game-implementations/games/_common.ts
@@ -17,14 +17,22 @@ import type {
 	GPTDerivers,
 	GPTGoalFormatters,
 	GPTGoalProgressFormatters,
-	GPTMetricValidators,
+	GPTChartSpecificMetricValidators,
 	GPTProfileCalculators,
 	GPTScoreCalculators,
 	GPTSessionCalculators,
 	PBMergeFunction,
 	ScoreCalculator,
+	ScoreValidator,
 } from "game-implementations/types";
-import type { GPTStrings, GradeBoundary, integer, SpecificUserGameStats } from "tachi-common";
+import type {
+	GPTStrings,
+	GradeBoundary,
+	integer,
+	SpecificUserGameStats,
+	GPTString,
+	ScoreDocument,
+} from "tachi-common";
 
 export const EX_SCORE_CHECK: ChartSpecificMetricValidator<IIDXLikes> = (exScore, chart) => {
 	if (exScore < 0) {
@@ -58,7 +66,23 @@ export const IIDXLIKE_DERIVERS: GPTDerivers<IIDXLikes> = {
 	},
 };
 
-export const IIDXLIKE_VALIDATORS: GPTMetricValidators<IIDXLikes> = { score: EX_SCORE_CHECK };
+export const IIDXLIKE_VALIDATORS: GPTChartSpecificMetricValidators<IIDXLikes> = {
+	score: EX_SCORE_CHECK,
+};
+
+export const IIDXLIKE_SCORE_VALIDATORS: Array<ScoreValidator<IIDXLikes>> = [
+	(s) => {
+		const { pgreat, great } = s.scoreData.judgements;
+
+		if (IsNullish(pgreat) || IsNullish(great)) {
+			return;
+		}
+
+		if (pgreat * 2 + great !== s.scoreData.score) {
+			return `Expected PGreat*2 + Great to equal EX score. Got ${pgreat}*2 + ${great} but that wasn't equal to the EX score of ${s.scoreData.score}.`;
+		}
+	},
+];
 
 type SDVXLikes = GPTStrings["sdvx" | "usc"];
 
@@ -212,6 +236,28 @@ export const SDVXLIKE_PB_MERGERS: Array<PBMergeFunction<SDVXLikes>> = [
 
 export const SDVXLIKE_DEFAULT_MERGE_NAME = "Best Score";
 
+export const SDVXLIKE_SCORE_VALIDATORS: Array<ScoreValidator<SDVXLikes>> = [
+	(s) => {
+		if (s.scoreData.lamp === "PERFECT ULTIMATE CHAIN" && s.scoreData.score !== 10_000_000) {
+			return "Cannot have a PERFECT ULTIMATE CHAIN without a perfect score.";
+		}
+	},
+	(s) => {
+		const { near, miss } = s.scoreData.judgements;
+
+		if (s.scoreData.lamp === "PERFECT ULTIMATE CHAIN" && (miss ?? 0) + (near ?? 0) > 0) {
+			return "Cannot have a PERFECT ULTIMATE CHAIN with any nears or misses.";
+		} else if (s.scoreData.lamp === "ULTIMATE CHAIN" && (miss ?? 0) > 0) {
+			return "Cannot have an ULTIMATE CHAIN with non-zero miss count.";
+		}
+	},
+	(s) => {
+		if (s.scoreData.lamp === "ULTIMATE CHAIN" && s.scoreData.score < 5_000_000) {
+			return "Cannot have an ULTIMATE CHAIN with a score less than 5m.";
+		}
+	},
+];
+
 export const SGLCalc: ScoreCalculator<GPTStrings["bms" | "pms"]> = (scoreData, chart) => {
 	const ecValue = chart.data.sglEC ?? 0;
 	const hcValue = chart.data.sglHC ?? 0;
@@ -281,3 +327,29 @@ export function GradeGoalFormatter<G extends string>(
 	// otherwise, return whichever is closer.
 	return closer === "lower" ? lower : upper;
 }
+
+/**
+ * Run all of the provided validators on the given score.
+ *
+ * @returns undefined on success, an array of error messages (strings) on failure.
+ */
+export function RunValidators<GPT extends GPTString>(
+	validators: Array<ScoreValidator<GPT>>,
+	score: ScoreDocument<GPT>
+) {
+	const errs = [];
+
+	for (const validator of validators) {
+		const err = validator(score);
+
+		if (err !== undefined) {
+			errs.push(err);
+		}
+	}
+
+	if (errs.length === 0) {
+		return;
+	}
+
+	return errs;
+}
diff --git a/server/src/game-implementations/games/bms-pms.test.ts b/server/src/game-implementations/games/bms-pms.test.ts
index dd4a96110..b36a73ab7 100644
--- a/server/src/game-implementations/games/bms-pms.test.ts
+++ b/server/src/game-implementations/games/bms-pms.test.ts
@@ -143,18 +143,18 @@ for (const [game, playtype, impl] of [
 	});
 
 	t.test("Validators", (t) => {
-		t.equal(impl.validators.score(1000, chart as any), true);
-		t.equal(impl.validators.score(0, chart as any), true);
-		t.equal(impl.validators.score(chart.data.notecount * 2, chart as any), true);
+		t.equal(impl.chartSpecificValidators.score(1000, chart as any), true);
+		t.equal(impl.chartSpecificValidators.score(0, chart as any), true);
+		t.equal(impl.chartSpecificValidators.score(chart.data.notecount * 2, chart as any), true);
 
 		TestSnapshot(
 			t,
-			impl.validators.score(-1, chart as any),
+			impl.chartSpecificValidators.score(-1, chart as any),
 			`EX Score Validator ${playtype}: negative`
 		);
 		TestSnapshot(
 			t,
-			impl.validators.score(chart.data.notecount * 2 + 1, chart as any),
+			impl.chartSpecificValidators.score(chart.data.notecount * 2 + 1, chart as any),
 			`EX Score Validator ${playtype}: excessive`
 		);
 
diff --git a/server/src/game-implementations/games/bms-pms.ts b/server/src/game-implementations/games/bms-pms.ts
index 3e8dac50e..d1c9d45be 100644
--- a/server/src/game-implementations/games/bms-pms.ts
+++ b/server/src/game-implementations/games/bms-pms.ts
@@ -1,9 +1,9 @@
 import {
 	GoalFmtPercent,
-	GoalFmtScore,
 	GoalOutOfFmtPercent,
 	GradeGoalFormatter,
 	IIDXLIKE_DERIVERS,
+	IIDXLIKE_SCORE_VALIDATORS,
 	IIDXLIKE_VALIDATORS,
 	SGLCalc,
 } from "./_common";
@@ -33,7 +33,7 @@ const BMS_PMS_MERGERS: Array<PBMergeFunction<GPTStrings["bms" | "pms"]>> = [
 
 const BMS_IMPL: GPTServerImplementation<GPTStrings["bms" | "pms"]> = {
 	derivers: IIDXLIKE_DERIVERS,
-	validators: IIDXLIKE_VALIDATORS,
+	chartSpecificValidators: IIDXLIKE_VALIDATORS,
 	scoreCalcs: { sieglinde: SGLCalc },
 	sessionCalcs: { sieglinde: SessionAvgBest10For("sieglinde") },
 	profileCalcs: { sieglinde: ProfileAvgBestN("sieglinde", 20) },
@@ -77,6 +77,7 @@ const BMS_IMPL: GPTServerImplementation<GPTStrings["bms" | "pms"]> = {
 	},
 	pbMergeFunctions: BMS_PMS_MERGERS,
 	defaultMergeRefName: "Best Score",
+	scoreValidators: IIDXLIKE_SCORE_VALIDATORS,
 };
 
 export const BMS_14K_IMPL: GPTServerImplementation<"bms:14K"> = BMS_IMPL;
diff --git a/server/src/game-implementations/games/chunithm.ts b/server/src/game-implementations/games/chunithm.ts
index 06297a5dd..c52b3a634 100644
--- a/server/src/game-implementations/games/chunithm.ts
+++ b/server/src/game-implementations/games/chunithm.ts
@@ -8,7 +8,7 @@ import { IsNullish } from "utils/misc";
 import type { GPTServerImplementation } from "game-implementations/types";
 
 export const CHUNITHM_IMPL: GPTServerImplementation<"chunithm:Single"> = {
-	validators: {},
+	chartSpecificValidators: {},
 	derivers: {
 		grade: ({ score }) => GetGrade(CHUNITHM_GBOUNDARIES, score),
 	},
@@ -72,4 +72,40 @@ export const CHUNITHM_IMPL: GPTServerImplementation<"chunithm:Single"> = {
 		}),
 	],
 	defaultMergeRefName: "Best Score",
+	scoreValidators: [
+		(s) => {
+			if (s.scoreData.lamp === "ALL JUSTICE CRITICAL" && s.scoreData.score !== 1_010_000) {
+				return "An ALL JUSTICE CRITICAL must have a score of 1.01 million.";
+			}
+
+			if (s.scoreData.lamp !== "ALL JUSTICE CRITICAL" && s.scoreData.score === 1_010_000) {
+				return "A score of 1.01 million must have a lamp of ALL JUSTICE CRITICAL.";
+			}
+		},
+		(s) => {
+			let { attack, justice, miss } = s.scoreData.judgements;
+
+			justice ??= 0;
+			attack ??= 0;
+			miss ??= 0;
+
+			if (s.scoreData.lamp === "ALL JUSTICE CRITICAL") {
+				if (attack + justice + miss > 0) {
+					return "Cannot have an ALL JUSTICE CRITICAL with any non-jcrit judgements.";
+				}
+			}
+
+			if (s.scoreData.lamp === "ALL JUSTICE") {
+				if (attack + miss > 0) {
+					return "Cannot have an ALL JUSTICE if not all hits were justice or better.";
+				}
+			}
+
+			if (s.scoreData.lamp === "FULL COMBO") {
+				if (miss > 0) {
+					return "Cannot have a FULL COMBO if the score has misses.";
+				}
+			}
+		},
+	],
 };
diff --git a/server/src/game-implementations/games/gitadora.ts b/server/src/game-implementations/games/gitadora.ts
index 250217846..99725ac82 100644
--- a/server/src/game-implementations/games/gitadora.ts
+++ b/server/src/game-implementations/games/gitadora.ts
@@ -37,7 +37,7 @@ async function CalculateGitadoraSkill(game: Game, playtype: Playtype, userID: in
 }
 
 const GITADORA_IMPL: GPTServerImplementation<"gitadora:Dora" | "gitadora:Gita"> = {
-	validators: {},
+	chartSpecificValidators: {},
 	derivers: {
 		grade: ({ percent }) => GetGrade(GITADORA_GBOUNDARIES, percent),
 	},
@@ -115,6 +115,7 @@ const GITADORA_IMPL: GPTServerImplementation<"gitadora:Dora" | "gitadora:Gita">
 		}),
 	],
 	defaultMergeRefName: "Best Percent",
+	scoreValidators: [],
 };
 
 export const GITADORA_GITA_IMPL: GPTServerImplementation<"gitadora:Gita"> = GITADORA_IMPL;
diff --git a/server/src/game-implementations/games/iidx.test.ts b/server/src/game-implementations/games/iidx.test.ts
index 0b998ca54..05d8b2e96 100644
--- a/server/src/game-implementations/games/iidx.test.ts
+++ b/server/src/game-implementations/games/iidx.test.ts
@@ -102,21 +102,21 @@ t.test("IIDX Implementation", (t) => {
 			["SP", IIDX_SP_IMPL],
 			["DP", IIDX_DP_IMPL],
 		] as const) {
-			t.equal(impl.validators.score(1000, Testing511SPA as any), true);
-			t.equal(impl.validators.score(0, Testing511SPA as any), true);
+			t.equal(impl.chartSpecificValidators.score(1000, Testing511SPA as any), true);
+			t.equal(impl.chartSpecificValidators.score(0, Testing511SPA as any), true);
 			t.equal(
-				impl.validators.score(Testing511SPA.data.notecount * 2, Testing511SPA as any),
+				impl.chartSpecificValidators.score(Testing511SPA.data.notecount * 2, Testing511SPA as any),
 				true
 			);
 
 			TestSnapshot(
 				t,
-				impl.validators.score(-1, Testing511SPA as any),
+				impl.chartSpecificValidators.score(-1, Testing511SPA as any),
 				`EX Score Validator ${playtype}: negative`
 			);
 			TestSnapshot(
 				t,
-				impl.validators.score(Testing511SPA.data.notecount * 2 + 1, Testing511SPA as any),
+				impl.chartSpecificValidators.score(Testing511SPA.data.notecount * 2 + 1, Testing511SPA as any),
 				`EX Score Validator ${playtype}: excessive`
 			);
 		}
diff --git a/server/src/game-implementations/games/iidx.ts b/server/src/game-implementations/games/iidx.ts
index 4246603d1..b52112349 100644
--- a/server/src/game-implementations/games/iidx.ts
+++ b/server/src/game-implementations/games/iidx.ts
@@ -3,6 +3,7 @@ import {
 	GoalOutOfFmtPercent,
 	GradeGoalFormatter,
 	IIDXLIKE_DERIVERS,
+	IIDXLIKE_SCORE_VALIDATORS,
 	IIDXLIKE_VALIDATORS,
 } from "./_common";
 import { CreatePBMergeFor } from "game-implementations/utils/pb-merge";
@@ -10,12 +11,14 @@ import { ProfileAvgBestN } from "game-implementations/utils/profile-calc";
 import { SessionAvgBest10For } from "game-implementations/utils/session-calc";
 import { PoyashiBPI } from "rg-stats";
 import { IIDXLIKE_GBOUNDARIES } from "tachi-common";
+import { IsNullish } from "utils/misc";
 import type {
 	GPTGoalFormatters,
 	GPTGoalProgressFormatters,
 	GPTServerImplementation,
 	PBMergeFunction,
 	ScoreCalculator,
+	ScoreValidator,
 } from "game-implementations/types";
 import type { GPTStrings } from "tachi-common";
 
@@ -110,7 +113,7 @@ const IIDX_GOAL_PG_FMT: GPTGoalProgressFormatters<"iidx:DP" | "iidx:SP"> = {
 
 export const IIDX_SP_IMPL: GPTServerImplementation<"iidx:SP"> = {
 	derivers: IIDXLIKE_DERIVERS,
-	validators: IIDXLIKE_VALIDATORS,
+	chartSpecificValidators: IIDXLIKE_VALIDATORS,
 	scoreCalcs: {
 		BPI: BPICalc,
 		ktLampRating: (scoreData, chart) => {
@@ -144,11 +147,12 @@ export const IIDX_SP_IMPL: GPTServerImplementation<"iidx:SP"> = {
 	goalOutOfFormatters: IIDX_GOAL_OO_FMT,
 	pbMergeFunctions: IIDX_MERGERS,
 	defaultMergeRefName: "Best Score",
+	scoreValidators: IIDXLIKE_SCORE_VALIDATORS,
 };
 
 export const IIDX_DP_IMPL: GPTServerImplementation<"iidx:DP"> = {
 	derivers: IIDXLIKE_DERIVERS,
-	validators: IIDXLIKE_VALIDATORS,
+	chartSpecificValidators: IIDXLIKE_VALIDATORS,
 	scoreCalcs: {
 		BPI: BPICalc,
 		ktLampRating: (scoreData, chart) => {
@@ -175,4 +179,5 @@ export const IIDX_DP_IMPL: GPTServerImplementation<"iidx:DP"> = {
 	goalOutOfFormatters: IIDX_GOAL_OO_FMT,
 	pbMergeFunctions: IIDX_MERGERS,
 	defaultMergeRefName: "Best Score",
+	scoreValidators: IIDXLIKE_SCORE_VALIDATORS,
 };
diff --git a/server/src/game-implementations/games/itg.ts b/server/src/game-implementations/games/itg.ts
index 089a00b0e..e2a838355 100644
--- a/server/src/game-implementations/games/itg.ts
+++ b/server/src/game-implementations/games/itg.ts
@@ -8,7 +8,7 @@ import { NumToDP } from "utils/misc";
 import type { GPTServerImplementation } from "game-implementations/types";
 
 export const ITG_STAMINA_IMPL: GPTServerImplementation<"itg:Stamina"> = {
-	validators: {},
+	chartSpecificValidators: {},
 	derivers: {
 		finalPercent: (metrics) => {
 			// *important*
@@ -136,4 +136,46 @@ export const ITG_STAMINA_IMPL: GPTServerImplementation<"itg:Stamina"> = {
 
 	// this name sucks, what should we do instead? TODO.
 	defaultMergeRefName: "Best Result",
+
+	scoreValidators: [
+		(s) => {
+			if (s.scoreData.lamp !== "FAILED" && s.scoreData.survivedPercent < 100) {
+				return "Cannot clear a chart that you didn't survive 100% of.";
+			}
+		},
+		(s) => {
+			let { fantastic, excellent, great, decent, wayoff, miss } = s.scoreData.judgements;
+
+			fantastic ??= 0;
+			excellent ??= 0;
+			great ??= 0;
+			decent ??= 0;
+			wayoff ??= 0;
+			miss ??= 0;
+
+			if (s.scoreData.lamp === "QUINT") {
+				if (fantastic + excellent + great + decent + wayoff + miss > 0) {
+					return "Cannot have a QUINT with any fantastic (or worse) judgements.";
+				}
+			}
+
+			if (s.scoreData.lamp === "QUAD") {
+				if (excellent + great + decent + wayoff + miss > 0) {
+					return "Cannot have a QUAD with any excellent (or worse) judgements.";
+				}
+			}
+
+			if (s.scoreData.lamp === "FULL EXCELLENT COMBO") {
+				if (great + decent + wayoff + miss > 0) {
+					return "Cannot have a FULL EXCELLENT COMBO with any great (or worse) judgements.";
+				}
+			}
+
+			if (s.scoreData.lamp === "FULL COMBO") {
+				if (decent + wayoff + miss > 0) {
+					return "Cannot have a FULL COMBO with any combo breaks.";
+				}
+			}
+		},
+	],
 };
diff --git a/server/src/game-implementations/games/jubeat.test.ts b/server/src/game-implementations/games/jubeat.test.ts
index aa7e63400..d8ce7f013 100644
--- a/server/src/game-implementations/games/jubeat.test.ts
+++ b/server/src/game-implementations/games/jubeat.test.ts
@@ -61,18 +61,18 @@ t.test("Jubeat Implementation", (t) => {
 
 	t.test("Music Rate Validator", (t) => {
 		t.equal(
-			JUBEAT_IMPL.validators.musicRate(80, TestingJubeatChart),
+			JUBEAT_IMPL.chartSpecificValidators.musicRate(80, TestingJubeatChart),
 			true,
 			"normal music rate"
 		);
-		t.equal(JUBEAT_IMPL.validators.musicRate(0, TestingJubeatChart), true, "0 music rate");
+		t.equal(JUBEAT_IMPL.chartSpecificValidators.musicRate(0, TestingJubeatChart), true, "0 music rate");
 		t.equal(
-			JUBEAT_IMPL.validators.musicRate(100, TestingJubeatChart),
+			JUBEAT_IMPL.chartSpecificValidators.musicRate(100, TestingJubeatChart),
 			true,
 			"perfect music rate"
 		);
 		t.equal(
-			JUBEAT_IMPL.validators.musicRate(
+			JUBEAT_IMPL.chartSpecificValidators.musicRate(
 				120,
 				dmf(TestingJubeatChart, {
 					difficulty: "HARD ADV",
@@ -84,12 +84,12 @@ t.test("Jubeat Implementation", (t) => {
 
 		TestSnapshot(
 			t,
-			JUBEAT_IMPL.validators.musicRate(-1, TestingJubeatChart),
+			JUBEAT_IMPL.chartSpecificValidators.musicRate(-1, TestingJubeatChart),
 			`Jubeat Music Rate Validator: negative`
 		);
 		TestSnapshot(
 			t,
-			JUBEAT_IMPL.validators.musicRate(
+			JUBEAT_IMPL.chartSpecificValidators.musicRate(
 				100.1,
 				dmf(TestingJubeatChart, {
 					difficulty: "ADV",
@@ -99,7 +99,7 @@ t.test("Jubeat Implementation", (t) => {
 		);
 		TestSnapshot(
 			t,
-			JUBEAT_IMPL.validators.musicRate(
+			JUBEAT_IMPL.chartSpecificValidators.musicRate(
 				120.1,
 				dmf(TestingJubeatChart, {
 					difficulty: "HARD ADV",
diff --git a/server/src/game-implementations/games/jubeat.ts b/server/src/game-implementations/games/jubeat.ts
index fdef19c11..63b3cf919 100644
--- a/server/src/game-implementations/games/jubeat.ts
+++ b/server/src/game-implementations/games/jubeat.ts
@@ -137,7 +137,7 @@ async function CalculateJubility(game: Game, playtype: Playtype, userID: integer
 }
 
 export const JUBEAT_IMPL: GPTServerImplementation<"jubeat:Single"> = {
-	validators: {
+	chartSpecificValidators: {
 		musicRate: (rate, chart) => {
 			switch (chart.difficulty) {
 				case "BSC":
@@ -227,4 +227,44 @@ export const JUBEAT_IMPL: GPTServerImplementation<"jubeat:Single"> = {
 		}),
 	],
 	defaultMergeRefName: "Best Music Rate",
+	scoreValidators: [
+		(s) => {
+			if (s.scoreData.lamp === "EXCELLENT" && s.scoreData.score !== 1_000_000) {
+				return `An EXCELLENT lamp must be accompanied with a score of 1 million.`;
+			}
+
+			if (s.scoreData.lamp !== "EXCELLENT" && s.scoreData.score === 1_000_000) {
+				return `A score of 1 million must be accompanied with an EXCELLENT lamp.`;
+			}
+		},
+		(s) => {
+			let { good, great, miss, poor } = s.scoreData.judgements;
+
+			great ??= 0;
+			good ??= 0;
+			poor ??= 0;
+			miss ??= 0;
+
+			if (s.scoreData.lamp === "EXCELLENT") {
+				if (good + great + miss + poor > 0) {
+					return "An EXCELLENT lamp can't have any non-perfect judgements.";
+				}
+			}
+
+			if (s.scoreData.lamp === "FULL COMBO") {
+				if (miss > 0) {
+					return "A FULL COMBO cannot have any misses.";
+				}
+			}
+		},
+		(s) => {
+			if (s.scoreData.score < 700_000 && s.scoreData.lamp !== "FAILED") {
+				return "A score of <700k must be a fail.";
+			}
+
+			if (s.scoreData.score >= 700_000 && s.scoreData.lamp === "FAILED") {
+				return "A score >=700k must be a clear.";
+			}
+		},
+	],
 };
diff --git a/server/src/game-implementations/games/maimaidx.ts b/server/src/game-implementations/games/maimaidx.ts
index c4d0a38fb..843343613 100644
--- a/server/src/game-implementations/games/maimaidx.ts
+++ b/server/src/game-implementations/games/maimaidx.ts
@@ -68,7 +68,7 @@ async function CalculateMaimaiDXRate(game: Game, playtype: Playtype, userID: int
 }
 
 export const MAIMAIDX_IMPL: GPTServerImplementation<"maimaidx:Single"> = {
-	validators: {},
+	chartSpecificValidators: {},
 	derivers: {
 		grade: ({ percent }) => GetGrade(MAIMAIDX_GBOUNDARIES, percent),
 	},
@@ -137,4 +137,15 @@ export const MAIMAIDX_IMPL: GPTServerImplementation<"maimaidx:Single"> = {
 		}),
 	],
 	defaultMergeRefName: "Best Percent",
+	scoreValidators: [
+		(s) => {
+			if (s.scoreData.lamp === "ALL PERFECT+" && s.scoreData.percent !== 101) {
+				return "Cannot have an ALL PERFECT+ without 101%.";
+			}
+
+			if (s.scoreData.lamp !== "ALL PERFECT+" && s.scoreData.percent === 101) {
+				return "A score of 101% should be an ALL PERFECT+";
+			}
+		},
+	],
 };
diff --git a/server/src/game-implementations/games/museca.ts b/server/src/game-implementations/games/museca.ts
index 1395be4da..aa972e3d1 100644
--- a/server/src/game-implementations/games/museca.ts
+++ b/server/src/game-implementations/games/museca.ts
@@ -7,7 +7,7 @@ import { FmtNum, GetGrade, MUSECA_GBOUNDARIES } from "tachi-common";
 import type { GPTServerImplementation } from "game-implementations/types";
 
 export const MUSECA_IMPL: GPTServerImplementation<"museca:Single"> = {
-	validators: {},
+	chartSpecificValidators: {},
 	derivers: {
 		grade: ({ score }) => GetGrade(MUSECA_GBOUNDARIES, score),
 	},
@@ -42,4 +42,38 @@ export const MUSECA_IMPL: GPTServerImplementation<"museca:Single"> = {
 		}),
 	],
 	defaultMergeRefName: "Best Score",
+	scoreValidators: [
+		(s) => {
+			if (s.scoreData.lamp === "PERFECT CONNECT ALL" && s.scoreData.score !== 1_000_000) {
+				return "A PERFECT CONNECT ALL must have a score of 1 million.";
+			}
+
+			if (s.scoreData.score === 1_000_000 && s.scoreData.lamp !== "PERFECT CONNECT ALL") {
+				return "A perfect score of 1 million must have a lamp of PERFECT CONNECT ALL.";
+			}
+		},
+		(s) => {
+			let { miss, near } = s.scoreData.judgements;
+
+			miss ??= 0;
+			near ??= 0;
+
+			if (s.scoreData.lamp === "PERFECT CONNECT ALL" && miss + near > 0) {
+				return "Cannot have a PERFECT CONNECT ALL with any nears or misses.";
+			}
+
+			if (s.scoreData.lamp === "CONNECT ALL" && miss > 0) {
+				return "Cannot have a CONNECT ALL with any misses.";
+			}
+		},
+		(s) => {
+			if (s.scoreData.score < 800_000 && s.scoreData.lamp !== "FAILED") {
+				return "A score of <800k must be a fail.";
+			}
+
+			if (s.scoreData.score >= 800_000 && s.scoreData.lamp === "FAILED") {
+				return "A score of >=800k must be a clear.";
+			}
+		},
+	],
 };
diff --git a/server/src/game-implementations/games/popn.ts b/server/src/game-implementations/games/popn.ts
index d288a5be9..42e1a29e5 100644
--- a/server/src/game-implementations/games/popn.ts
+++ b/server/src/game-implementations/games/popn.ts
@@ -32,7 +32,7 @@ export function PopnClearMedalToLamp(
 }
 
 export const POPN_9B_IMPL: GPTServerImplementation<"popn:9B"> = {
-	validators: {},
+	chartSpecificValidators: {},
 	derivers: {
 		lamp: ({ clearMedal }) => PopnClearMedalToLamp(clearMedal),
 		grade: ({ score, clearMedal }) => {
@@ -114,4 +114,83 @@ export const POPN_9B_IMPL: GPTServerImplementation<"popn:9B"> = {
 		}),
 	],
 	defaultMergeRefName: "Best Score",
+	scoreValidators: [
+		(s) => {
+			const { bad, good } = s.scoreData.judgements;
+
+			if (s.scoreData.lamp === "PERFECT") {
+				const mistakes = (bad ?? 0) + (good ?? 0);
+
+				if (mistakes > 0) {
+					return "Cannot have a PERFECT lamp with any bads or goods.";
+				}
+			} else if (s.scoreData.lamp === "FULL COMBO") {
+				const mistakes = bad ?? 0;
+
+				if (mistakes > 0) {
+					return "Cannot have a FULL COMBO lamp with any bads.";
+				}
+			}
+		},
+		// clear medal bad/good checks.
+		(s) => {
+			let { bad, good } = s.scoreData.judgements;
+
+			bad ??= 0;
+			good ??= 0;
+
+			switch (s.scoreData.clearMedal) {
+				case "fullComboStar": {
+					if (good > 5 || good < 1) {
+						return "Must have between 1-5 goods for a full combo star.";
+					}
+
+					break;
+				}
+
+				case "fullComboDiamond": {
+					if (good > 20 || good < 6) {
+						return "Must have between 6-20 goods for a full combo diamond.";
+					}
+
+					break;
+				}
+
+				case "fullComboCircle": {
+					if (good < 21) {
+						return "Must have >21 goods for a full combo circle.";
+					}
+
+					break;
+				}
+
+				case "clearStar": {
+					if (bad > 5 || bad < 1) {
+						return "Must have between 1-5 bads for a clear star.";
+					}
+
+					break;
+				}
+
+				case "clearDiamond": {
+					if (bad > 20 || bad < 6) {
+						return "Must have between 6-20 bads for a clear diamond.";
+					}
+
+					break;
+				}
+
+				case "clearCircle": {
+					if (bad < 21) {
+						return "Must have between >21 bads for a clear circle.";
+					}
+
+					break;
+				}
+
+				// can't validate the fails since we don't have the gauge info.
+				default:
+			}
+		},
+	],
 };
diff --git a/server/src/game-implementations/games/sdvx.test.ts b/server/src/game-implementations/games/sdvx.test.ts
index 8dce1ce75..afed5227b 100644
--- a/server/src/game-implementations/games/sdvx.test.ts
+++ b/server/src/game-implementations/games/sdvx.test.ts
@@ -34,12 +34,12 @@ const mockPB = mkMockPB("sdvx", "Single", TestingSDVXAlbidaChart, scoreData);
 
 t.test("SDVX Implementation", (t) => {
 	t.test("EX Score Validator", (t) => {
-		t.equal(SDVX_IMPL.validators.exScore(1000, TestingSDVXAlbidaChart), true);
-		t.equal(SDVX_IMPL.validators.exScore(0, TestingSDVXAlbidaChart), true);
+		t.equal(SDVX_IMPL.chartSpecificValidators.exScore(1000, TestingSDVXAlbidaChart), true);
+		t.equal(SDVX_IMPL.chartSpecificValidators.exScore(0, TestingSDVXAlbidaChart), true);
 
 		TestSnapshot(
 			t,
-			SDVX_IMPL.validators.exScore(-1, TestingSDVXAlbidaChart),
+			SDVX_IMPL.chartSpecificValidators.exScore(-1, TestingSDVXAlbidaChart),
 			`EX Score Validator SDVX: negative`
 		);
 
diff --git a/server/src/game-implementations/games/sdvx.ts b/server/src/game-implementations/games/sdvx.ts
index 95c738582..30e17dcdf 100644
--- a/server/src/game-implementations/games/sdvx.ts
+++ b/server/src/game-implementations/games/sdvx.ts
@@ -8,13 +8,14 @@ import {
 	SDVXLIKE_PB_MERGERS,
 	SDVXLIKE_PROFILE_CALCS,
 	SDVXLIKE_SCORE_CALCS,
+	SDVXLIKE_SCORE_VALIDATORS,
 	SDVXLIKE_SESSION_CALCS,
 } from "./_common";
 import type { GPTServerImplementation } from "game-implementations/types";
 
 export const SDVX_IMPL: GPTServerImplementation<"sdvx:Single"> = {
 	derivers: SDVXLIKE_DERIVERS,
-	validators: {
+	chartSpecificValidators: {
 		exScore: (exScore, chart) => {
 			if (exScore < 0) {
 				return `EX Score must be non-negative. Got ${exScore}`;
@@ -37,4 +38,5 @@ export const SDVX_IMPL: GPTServerImplementation<"sdvx:Single"> = {
 	goalOutOfFormatters: SDVXLIKE_GOAL_OO_FMT,
 	pbMergeFunctions: SDVXLIKE_PB_MERGERS,
 	defaultMergeRefName: SDVXLIKE_DEFAULT_MERGE_NAME,
+	scoreValidators: SDVXLIKE_SCORE_VALIDATORS,
 };
diff --git a/server/src/game-implementations/games/usc.ts b/server/src/game-implementations/games/usc.ts
index 7075df7ac..0972d9053 100644
--- a/server/src/game-implementations/games/usc.ts
+++ b/server/src/game-implementations/games/usc.ts
@@ -9,13 +9,14 @@ import {
 	SDVXLIKE_GOAL_OO_FMT,
 	SDVXLIKE_DEFAULT_MERGE_NAME,
 	SDVXLIKE_PB_MERGERS,
+	SDVXLIKE_SCORE_VALIDATORS,
 } from "./_common";
 import type { GPTServerImplementation } from "game-implementations/types";
 import type { GPTStrings } from "tachi-common";
 
 const USC_IMPL: GPTServerImplementation<GPTStrings["usc"]> = {
 	derivers: SDVXLIKE_DERIVERS,
-	validators: {},
+	chartSpecificValidators: {},
 	scoreCalcs: SDVXLIKE_SCORE_CALCS,
 	sessionCalcs: SDVXLIKE_SESSION_CALCS,
 	profileCalcs: SDVXLIKE_PROFILE_CALCS,
@@ -25,6 +26,7 @@ const USC_IMPL: GPTServerImplementation<GPTStrings["usc"]> = {
 	goalOutOfFormatters: SDVXLIKE_GOAL_OO_FMT,
 	pbMergeFunctions: SDVXLIKE_PB_MERGERS,
 	defaultMergeRefName: SDVXLIKE_DEFAULT_MERGE_NAME,
+	scoreValidators: SDVXLIKE_SCORE_VALIDATORS,
 };
 
 export const USC_KEYBOARD_IMPL: GPTServerImplementation<"usc:Keyboard"> = USC_IMPL;
diff --git a/server/src/game-implementations/games/wacca.test.ts b/server/src/game-implementations/games/wacca.test.ts
index 1b5f0f687..f78b6cbea 100644
--- a/server/src/game-implementations/games/wacca.test.ts
+++ b/server/src/game-implementations/games/wacca.test.ts
@@ -1,3 +1,4 @@
+import { RunValidators } from "./_common";
 import { WACCA_IMPL } from "./wacca";
 import db from "external/mongo/db";
 import CreateLogCtx from "lib/logger/logger";
@@ -6,8 +7,10 @@ import { WACCA_SINGLE_CONF } from "tachi-common/config/game-support/wacca";
 import t from "tap";
 import { dmf, mkMockPB, mkMockScore } from "test-utils/misc";
 import ResetDBState from "test-utils/resets";
+import { TestSnapshot } from "test-utils/single-process-snapshot";
 import { TestingWaccaPupaExp } from "test-utils/test-data";
-import type { ProvidedMetrics, ScoreData } from "tachi-common";
+import type { ProvidedMetrics, ScoreData, ScoreDocument } from "tachi-common";
+import type { DeepPartial } from "utils/types";
 
 const GRADES = WACCA_SINGLE_CONF.derivedMetrics.grade.values;
 const LAMPS = WACCA_SINGLE_CONF.providedMetrics.lamp.values;
@@ -167,5 +170,42 @@ t.test("WACCA Implementation", (t) => {
 		t.end();
 	});
 
+	t.test("Score Validations", (t) => {
+		const f = (s: DeepPartial<ScoreDocument<"wacca:Single">>) =>
+			RunValidators(WACCA_IMPL.scoreValidators, dmf(mockScore, s));
+
+		t.strictSame(f({ scoreData: { lamp: "ALL MARVELOUS", score: 1_000_000 } }), undefined);
+		t.strictSame(f({ scoreData: { lamp: "FULL COMBO", judgements: { miss: 0 } } }), undefined);
+
+		TestSnapshot(
+			t,
+			f({ scoreData: { lamp: "ALL MARVELOUS", score: 999_999 } }),
+			"WACCA IMPL Validators: Should disallow ALL MARVELOUS with non-perfect score."
+		);
+		TestSnapshot(
+			t,
+			f({ scoreData: { lamp: "FULL COMBO", judgements: { miss: 1 } } }),
+			`WACCA IMPL Validators: Should disallow FC with miss`
+		);
+
+		TestSnapshot(
+			t,
+			f({ scoreData: { lamp: "ALL MARVELOUS", judgements: { good: 1 } } }),
+			"WACCA IMPL Validators: Should disallow ALL MARVELOUS with non-perfect good judgements."
+		);
+		TestSnapshot(
+			t,
+			f({ scoreData: { lamp: "ALL MARVELOUS", judgements: { great: 1 } } }),
+			"WACCA IMPL Validators: Should disallow ALL MARVELOUS with non-perfect good judgements."
+		);
+		TestSnapshot(
+			t,
+			f({ scoreData: { lamp: "ALL MARVELOUS", judgements: { miss: 1 } } }),
+			"WACCA IMPL Validators: Should disallow ALL MARVELOUS with non-perfect good judgements."
+		);
+
+		t.end();
+	});
+
 	t.end();
 });
diff --git a/server/src/game-implementations/games/wacca.ts b/server/src/game-implementations/games/wacca.ts
index 07db05f5d..8f6de3a11 100644
--- a/server/src/game-implementations/games/wacca.ts
+++ b/server/src/game-implementations/games/wacca.ts
@@ -68,7 +68,7 @@ async function CalculateWACCARate(game: Game, playtype: Playtype, userID: intege
 }
 
 export const WACCA_IMPL: GPTServerImplementation<"wacca:Single"> = {
-	validators: {},
+	chartSpecificValidators: {},
 	derivers: {
 		grade: ({ score }) => GetGrade(WACCA_GBOUNDARIES, score),
 	},
@@ -132,4 +132,43 @@ export const WACCA_IMPL: GPTServerImplementation<"wacca:Single"> = {
 		}),
 	],
 	defaultMergeRefName: "Best Score",
+
+	scoreValidators: [
+		(s) => {
+			if (s.scoreData.lamp === "ALL MARVELOUS" && s.scoreData.score !== 1_000_000) {
+				return `ALL MARVELOUS scores must have a perfect score. Got ${s.scoreData.score} instead.`;
+			}
+
+			// goes both ways
+			if (s.scoreData.score === 1_000_000 && s.scoreData.lamp !== "ALL MARVELOUS") {
+				return `Perfect scores of 1 million must have ALL MARVELOUS as their lamp. Got ${s.scoreData.lamp} instead.`;
+			}
+		},
+		(s) => {
+			const { miss } = s.scoreData.judgements;
+
+			if (miss === null || miss === undefined || miss === 0) {
+				return;
+			}
+
+			if (s.scoreData.lamp === "FULL COMBO") {
+				return "Cannot have a FULL COMBO with misses.";
+			}
+
+			if (miss > 5 && s.scoreData.lamp === "MISSLESS") {
+				return "Cannot have a MISSLESS lamp with >5 misses.";
+			}
+		},
+		(s) => {
+			const { miss, good, great } = s.scoreData.judgements;
+
+			if (s.scoreData.lamp === "ALL MARVELOUS") {
+				const mistakes = (miss ?? 0) + (good ?? 0) + (great ?? 0);
+
+				if (mistakes > 0) {
+					return "Cannot have an ALL MARVELOUS if all judgements were not marvelous.";
+				}
+			}
+		},
+	],
 };
diff --git a/server/src/game-implementations/types.ts b/server/src/game-implementations/types.ts
index 6addc0db8..b4e00e774 100644
--- a/server/src/game-implementations/types.ts
+++ b/server/src/game-implementations/types.ts
@@ -109,7 +109,7 @@ export type PBMergeFunction<GPT extends GPTString> = (
  * The only metrics that need validators are those that have `chartDependentMax` set.
  * Otherwise, a validator is built into the ConfScoreMetric.
  */
-export type GPTMetricValidators<GPT extends GPTString> = {
+export type GPTChartSpecificMetricValidators<GPT extends GPTString> = {
 	[M in keyof AllConfMetrics[GPT] as AllConfMetrics[GPT][M] extends ChartDependentMax
 		? M
 		: never]: ChartSpecificMetricValidator<GPT>;
@@ -159,12 +159,35 @@ export type GPTGoalProgressFormatters<GPT extends GPTString> = {
 	[K in keyof ConfScoreMetrics[GPT]]: GoalProgressFormatter<GPT>;
 };
 
+/**
+ * Return nothing on success, and a string
+ * indicating what the error was on failure.
+ */
+export type ScoreValidator<GPT extends GPTString> = (
+	score: ScoreDocument<GPT>
+) => string | undefined;
+
 export interface GPTServerImplementation<GPT extends GPTString> {
-	validators: GPTMetricValidators<GPT>;
+	/**
+	 * For any chart-dependent metrics, such as EX Score for IIDX, how should we
+	 * validate they're correct?
+	 */
+	chartSpecificValidators: GPTChartSpecificMetricValidators<GPT>;
+
+	/**
+	 * How should we derive the derived metrics for this game?
+	 */
 	derivers: GPTDerivers<GPT>;
+
+	// assorted calculator functions
 	scoreCalcs: GPTScoreCalculators<GPT>;
 	sessionCalcs: GPTSessionCalculators<GPT>;
 	profileCalcs: GPTProfileCalculators<GPT>;
+
+	/**
+	 * For any "derived" classes for this game (i.e. classes that are the function
+	 * of the user's state), how should they work?
+	 */
 	classDerivers: GPTClassDerivers<GPT>;
 
 	/**
@@ -204,6 +227,17 @@ export interface GPTServerImplementation<GPT extends GPTString> {
 	 * metric. What should that be called?
 	 */
 	defaultMergeRefName: string;
+
+	/**
+	 * There are various things that should be true about scores for each game
+	 * that aren't already checked. This is for invariants that can't be tested
+	 * otherwise, like judgements properly summing up to the EX Score for IIDX, etc.
+	 *
+	 * These are for checking things that are *obviously* incorrect. For more subtle
+	 * incorrectnesses, like working out what the minimum possible full combo score
+	 * could be (which might be chart dependent, etc), don't bother.
+	 */
+	scoreValidators: Array<ScoreValidator<GPT>>;
 }
 
 export type GPTImplementations = {
diff --git a/server/src/lib/score-import/framework/score-importing/validate-score.ts b/server/src/lib/score-import/framework/score-importing/validate-score.ts
index be5340a0e..00a1b9f17 100644
--- a/server/src/lib/score-import/framework/score-importing/validate-score.ts
+++ b/server/src/lib/score-import/framework/score-importing/validate-score.ts
@@ -1,5 +1,6 @@
 import { InvalidScoreFailure } from "../common/converter-failures";
 import { GPT_SERVER_IMPLEMENTATIONS } from "game-implementations/game-implementations";
+import { RunValidators } from "game-implementations/games/_common";
 import { GetGPTConfig, GetGPTString } from "tachi-common";
 import type { ChartDocument, GPTString, ScoreDocument } from "tachi-common";
 import type { ConfScoreMetric } from "tachi-common/types/metrics";
@@ -14,6 +15,7 @@ import type { ConfScoreMetric } from "tachi-common/types/metrics";
 export function ValidateScore(score: ScoreDocument, chart: ChartDocument): void {
 	const gptString = GetGPTString(score.game, score.playtype);
 	const gptConfig = GetGPTConfig(gptString);
+	const gptImpl = GPT_SERVER_IMPLEMENTATIONS[gptString];
 
 	const errs: Array<string> = [];
 
@@ -47,6 +49,12 @@ export function ValidateScore(score: ScoreDocument, chart: ChartDocument): void
 		true
 	);
 
+	const moreErrors = RunValidators(gptImpl.scoreValidators as any, score);
+
+	if (moreErrors) {
+		errs.push(...moreErrors);
+	}
+
 	if (errs.length > 0) {
 		const errorStr = errs.length === 1 ? "error" : "errors";
 
@@ -102,7 +110,7 @@ function ValidateMetrics(
 
 				if (conf.chartDependentMax) {
 					// @ts-expect-error hack, this is fine. don't worry.
-					err = gptImpl.validators[metric](scoreVal, chart);
+					err = gptImpl.chartSpecificValidators[metric](scoreVal, chart);
 				} else {
 					err = conf.validate(scoreVal);
 				}
diff --git a/server/src/lib/targets/goal-utils.ts b/server/src/lib/targets/goal-utils.ts
index f1008dc71..06a3f2453 100644
--- a/server/src/lib/targets/goal-utils.ts
+++ b/server/src/lib/targets/goal-utils.ts
@@ -306,7 +306,7 @@ export async function ValidateGoalChartsAndCriteria(
 				}
 
 				// @ts-expect-error this is fine leave me alone
-				err = gptImpl.validators[criteria.key](criteria.value, chart);
+				err = gptImpl.chartSpecificValidators[criteria.key](criteria.value, chart);
 			} else {
 				err = config.validate(criteria.value);
 			}
diff --git a/server/src/server/router/ir/fervidex/router.test.ts b/server/src/server/router/ir/fervidex/router.test.ts
index 8f8b05edc..c0f6ad53c 100644
--- a/server/src/server/router/ir/fervidex/router.test.ts
+++ b/server/src/server/router/ir/fervidex/router.test.ts
@@ -456,9 +456,10 @@ t.test("POST /ir/fervidex/score/submit", (t) => {
 		t.strictSame(imp?.errors, [
 			{
 				type: "InvalidDatapoint",
-				message: `Got 2 errors when validating score:
+				message: `Got 3 errors when validating score:
 Invalid value for score, EX Score cannot be greater than 1572 for this chart. Got 9999.
-Invalid value for percent, Expected a number between 0 and 100. Got 636.0687022900763.`,
+Invalid value for percent, Expected a number between 0 and 100. Got 636.0687022900763.
+Expected PGreat*2 + Great to equal EX score. Got 34*2 + 0 but that wasn't equal to the EX score of 9999.`,
 			},
 		]);
 
diff --git a/server/src/test-utils/single-process-snapshot.ts b/server/src/test-utils/single-process-snapshot.ts
index 2b63e7bfb..e89a37d2f 100644
--- a/server/src/test-utils/single-process-snapshot.ts
+++ b/server/src/test-utils/single-process-snapshot.ts
@@ -22,7 +22,7 @@ export function WriteSnapshotData() {
 
 const snapshotData = ReadSnapshotData();
 
-export function TestSnapshot(t: Tap.Test, value: boolean | number | string, testName: string) {
+export function TestSnapshot(t: Tap.Test, value: any, testName: string) {
 	if (IsNonEmptyString(process.env.TAP_SNAPSHOT)) {
 		snapshotData[testName] = value;
 		WriteSnapshotData();
@@ -31,6 +31,6 @@ export function TestSnapshot(t: Tap.Test, value: boolean | number | string, test
 			return t.fail(`No snapshot exists for ${testName}. Have you ran pnpm snap?`);
 		}
 
-		t.equal(value, snapshotData[testName], `Snapshot: ${testName}`);
+		t.strictSame(value, snapshotData[testName], `Snapshot: ${testName}`);
 	}
 }
diff --git a/server/src/test-utils/snapshots/snapshot-data.json b/server/src/test-utils/snapshots/snapshot-data.json
index c7827f53c..cd23323d7 100644
--- a/server/src/test-utils/snapshots/snapshot-data.json
+++ b/server/src/test-utils/snapshots/snapshot-data.json
@@ -47,5 +47,15 @@
 	"EX Score Validator Controller: negative": "EX Score cannot be negative.",
 	"EX Score Validator Controller: excessive": "EX Score cannot be greater than 4512 for this chart.",
 	"EX Score Validator Keyboard: negative": "EX Score cannot be negative.",
-	"EX Score Validator Keyboard: excessive": "EX Score cannot be greater than 4512 for this chart."
+	"EX Score Validator Keyboard: excessive": "EX Score cannot be greater than 4512 for this chart.",
+	"WACCA IMPL Validators: Should disallow ALL MARVELOUS with non-perfect score.": [
+		"ALL MARVELOUS scores must have a perfect score. Got 999999 instead."
+	],
+	"WACCA IMPL Validators: Should disallow FC with miss": [
+		"Cannot have a FULL COMBO with misses."
+	],
+	"WACCA IMPL Validators: Should disallow ALL MARVELOUS with non-perfect good judgements.": [
+		"ALL MARVELOUS scores must have a perfect score. Got 953000 instead.",
+		"Cannot have an ALL MARVELOUS if all judgements were not marvelous."
+	]
 }
\ No newline at end of file