diff --git a/src/sys/nact.h b/src/sys/nact.h
index 33cd00f..8381e04 100644
--- a/src/sys/nact.h
+++ b/src/sys/nact.h
@@ -79,30 +79,30 @@ protected:
 	virtual void cmd_open_verb() = 0;
 
 	void cmd_a();
-	virtual void cmd_b() = 0;
-	virtual void cmd_d() = 0;
-	virtual void cmd_e() = 0;
+	virtual void cmd_b() { sco.unknown_command('B'); }
+	virtual void cmd_d() { sco.unknown_command('D'); }
+	virtual void cmd_e() { sco.unknown_command('E'); }
 	void cmd_f();
-	virtual void cmd_g() = 0;
-	virtual void cmd_h() = 0;
-	virtual void cmd_i() = 0;
-	virtual void cmd_j() = 0;
-	virtual void cmd_k() = 0;
-	virtual void cmd_l() = 0;
-	virtual void cmd_m() = 0;
-	virtual void cmd_n() = 0;
-	virtual void cmd_o() = 0;
-	virtual void cmd_p() = 0;
-	virtual void cmd_q() = 0;
+	virtual void cmd_g() { sco.unknown_command('G'); }
+	virtual void cmd_h() { sco.unknown_command('H'); }
+	virtual void cmd_i() { sco.unknown_command('I'); }
+	virtual void cmd_j() { sco.unknown_command('J'); }
+	virtual void cmd_k() { sco.unknown_command('K'); }
+	virtual void cmd_l() { sco.unknown_command('L'); }
+	virtual void cmd_m() { sco.unknown_command('M'); }
+	virtual void cmd_n() { sco.unknown_command('N'); }
+	virtual void cmd_o() { sco.unknown_command('O'); }
+	virtual void cmd_p() { sco.unknown_command('P'); }
+	virtual void cmd_q() { sco.unknown_command('Q'); }
 	void cmd_r();
 	void cmd_s();
-	virtual void cmd_t() = 0;
-	virtual void cmd_u() = 0;
-	virtual void cmd_v() = 0;
-	virtual void cmd_w() = 0;
+	virtual void cmd_t() { sco.unknown_command('T'); }
+	virtual void cmd_u() { sco.unknown_command('U'); }
+	virtual void cmd_v() { sco.unknown_command('V'); }
+	virtual void cmd_w() { sco.unknown_command('W'); }
 	void cmd_x();
-	virtual void cmd_y() = 0;
-	virtual void cmd_z() = 0;
+	virtual void cmd_y() { sco.unknown_command('Y'); }
+	virtual void cmd_z() { sco.unknown_command('Z'); }
 
 	// SYSTEM1
 	virtual void opening() {}
diff --git a/src/sys/nact_sys1.cpp b/src/sys/nact_sys1.cpp
index 4855810..f3146ba 100644
--- a/src/sys/nact_sys1.cpp
+++ b/src/sys/nact_sys1.cpp
@@ -30,24 +30,11 @@ public:
 protected:
 	void cmd_branch() override;
 	void cmd_open_verb() override;
-	void cmd_b() override;
-	void cmd_d() override;
-	void cmd_e() override;
 	void cmd_g() override;
-	void cmd_h() override;
-	void cmd_i() override;
-	void cmd_j() override;
-	void cmd_k() override;
 	void cmd_l() override;
-	void cmd_m() override;
-	void cmd_n() override;
-	void cmd_o() override;
 	void cmd_p() override;
 	void cmd_q() override;
-	void cmd_t() override;
 	void cmd_u() override;
-	void cmd_v() override;
-	void cmd_w() override;
 	void cmd_y() override;
 	void cmd_z() override;
 	uint16 cali() override;
@@ -364,24 +351,6 @@ top2:
 	}
 }
 
-void NACT_Sys1::cmd_b()
-{
-	// Unused
-	sco.unknown_command('B');
-}
-
-void NACT_Sys1::cmd_d()
-{
-	// Unused
-	sco.unknown_command('D');
-}
-
-void NACT_Sys1::cmd_e()
-{
-	// Unused
-	sco.unknown_command('E');
-}
-
 void NACT_Sys1::cmd_g()
 {
 	int page = sco.getd();
@@ -391,30 +360,6 @@ void NACT_Sys1::cmd_g()
 	ags->load_cg(page, -1);
 }
 
-void NACT_Sys1::cmd_h()
-{
-	// Unused
-	sco.unknown_command('H');
-}
-
-void NACT_Sys1::cmd_i()
-{
-	// Unused
-	sco.unknown_command('I');
-}
-
-void NACT_Sys1::cmd_j()
-{
-	// Unused
-	sco.unknown_command('J');
-}
-
-void NACT_Sys1::cmd_k()
-{
-	// Unused
-	sco.unknown_command('K');
-}
-
 void NACT_Sys1::cmd_l()
 {
 	int index = sco.getd();
@@ -427,24 +372,6 @@ void NACT_Sys1::cmd_l()
 	}
 }
 
-void NACT_Sys1::cmd_m()
-{
-	// Unused
-	sco.unknown_command('M');
-}
-
-void NACT_Sys1::cmd_n()
-{
-	// Unused
-	sco.unknown_command('N');
-}
-
-void NACT_Sys1::cmd_o()
-{
-	// Unused
-	sco.unknown_command('O');
-}
-
 void NACT_Sys1::cmd_p()
 {
 	int param = sco.getd();
@@ -476,12 +403,6 @@ void NACT_Sys1::cmd_q()
 	}
 }
 
-void NACT_Sys1::cmd_t()
-{
-	// Unused
-	sco.unknown_command('T');
-}
-
 void NACT_Sys1::cmd_u()
 {
 	int page = sco.getd();
@@ -492,18 +413,6 @@ void NACT_Sys1::cmd_u()
 	ags->load_cg(page, transparent);
 }
 
-void NACT_Sys1::cmd_v()
-{
-	// Unused
-	sco.unknown_command('V');
-}
-
-void NACT_Sys1::cmd_w()
-{
-	// Unused
-	sco.unknown_command('W');
-}
-
 void NACT_Sys1::cmd_y()
 {
 	int cmd = cali();
diff --git a/src/sys/nact_sys3.cpp b/src/sys/nact_sys3.cpp
index 89f5615..07eb97e 100644
--- a/src/sys/nact_sys3.cpp
+++ b/src/sys/nact_sys3.cpp
@@ -86,7 +86,6 @@ protected:
 	void cmd_branch() override;
 	void cmd_open_verb() override;
 	void cmd_b() override;
-	void cmd_d() override;
 	void cmd_e() override;
 	void cmd_g() override;
 	void cmd_h() override;
@@ -306,12 +305,6 @@ void NACT_Sys3::cmd_b()
 	}
 }
 
-void NACT_Sys3::cmd_d()
-{
-	// Unused
-	sco.unknown_command('D');
-}
-
 void NACT_Sys3::cmd_e()
 {
 	int index = cali();