diff --git a/src/mame/drivers/namcos23.cpp b/src/mame/drivers/namcos23.cpp
index 6493eeb41f2..dd55ada577c 100644
--- a/src/mame/drivers/namcos23.cpp
+++ b/src/mame/drivers/namcos23.cpp
@@ -5126,7 +5126,7 @@ ROM_END
 
 
 /* Games */
-#define GAME_FLAGS (MACHINE_NOT_WORKING | MACHINE_UNEMULATED_PROTECTION | MACHINE_IMPERFECT_GRAPHICS | MACHINE_IMPERFECT_SOUND)
+#define GAME_FLAGS (MACHINE_NOT_WORKING | MACHINE_UNEMULATED_PROTECTION | MACHINE_IMPERFECT_GRAPHICS )
 //    YEAR, NAME,        PARENT,   MACHINE,     INPUT,     INIT,                MNTR,  COMPANY, FULLNAME,                      FLAGS
 GAME( 1997, rapidrvr,    0,        gorgon,      rapidrvr,  namcos23_state, s23, ROT0, "Namco", "Rapid River (RD3 Ver. C)",     GAME_FLAGS ) // 97/11/27, USA
 GAME( 1997, rapidrvrv2c, rapidrvr, gorgon,      rapidrvr,  namcos23_state, s23, ROT0, "Namco", "Rapid River (RD2 Ver. C)",     GAME_FLAGS ) // 97/11/27, Europe