diff --git a/src/mame/drivers/mazerbla.cpp b/src/mame/drivers/mazerbla.cpp
index 5a0fb441a68..511269c5664 100644
--- a/src/mame/drivers/mazerbla.cpp
+++ b/src/mame/drivers/mazerbla.cpp
@@ -119,12 +119,12 @@ video z80
 
 #include "emu.h"
 #include "cpu/z80/z80.h"
+#include "machine/nvram.h"
 #include "sound/ay8910.h"
 #include "video/resnet.h"
 #include "video/mb_vcu.h"
 #include "screen.h"
 #include "speaker.h"
-#include "machine/nvram.h"
 
 
 #define MAZERBLA 0x01
@@ -1323,20 +1323,22 @@ static INPUT_PORTS_START( greatgun )
 	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_COIN1 )
 	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_START1 )
 	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_START2 )
-	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_BUTTON1 )
-	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_BUTTON2 )
-	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_BUTTON3 )
-	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_BUTTON4 )
+	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_BUTTON1 ) PORT_PLAYER(1) PORT_NAME("P1 Fire")
+	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_BUTTON1 ) PORT_PLAYER(2) PORT_NAME("P2 Fire")
+	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_UNUSED )
+	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_UNUSED )
 
 	PORT_START("STICK0_X")  /* Strobe 6: horizontal movement of gun */
-	PORT_BIT( 0xff, 0x80, IPT_AD_STICK_X ) PORT_SENSITIVITY(25) PORT_KEYDELTA(7) PORT_PLAYER(1)
+	PORT_BIT( 0xff, 0x80, IPT_LIGHTGUN_X ) PORT_MINMAX(0x00, 0xff) PORT_CROSSHAIR(X, 1.0, 0.0, 0) PORT_SENSITIVITY(25) PORT_KEYDELTA(7) PORT_PLAYER(1)
+
 	PORT_START("STICK0_Y")  /* Strobe 7: vertical movement of gun */
-	PORT_BIT( 0xff, 0x80, IPT_AD_STICK_Y ) PORT_SENSITIVITY(25) PORT_KEYDELTA(7) PORT_PLAYER(1)
+	PORT_BIT( 0xff, 0x80, IPT_LIGHTGUN_Y ) PORT_MINMAX(0x00, 0xff) PORT_CROSSHAIR(Y, 1.0, 0.0, 0) PORT_SENSITIVITY(25) PORT_KEYDELTA(7) PORT_PLAYER(1)
 
 	PORT_START("STICK1_X")  /* Strobe 8: horizontal movement of gun */
-	PORT_BIT( 0xff, 0x80, IPT_AD_STICK_X ) PORT_SENSITIVITY(25) PORT_KEYDELTA(7) PORT_PLAYER(2)
+	PORT_BIT( 0xff, 0x80, IPT_LIGHTGUN_X ) PORT_MINMAX(0x00, 0xff) PORT_CROSSHAIR(X, 1.0, 0.0, 0) PORT_SENSITIVITY(25) PORT_KEYDELTA(7) PORT_PLAYER(2)
+
 	PORT_START("STICK1_Y")  /* Strobe 9: vertical movement of gun */
-	PORT_BIT( 0xff, 0x80, IPT_AD_STICK_Y ) PORT_SENSITIVITY(25) PORT_KEYDELTA(7) PORT_PLAYER(2)
+	PORT_BIT( 0xff, 0x80, IPT_LIGHTGUN_Y ) PORT_MINMAX(0x00, 0xff) PORT_CROSSHAIR(Y, 1.0, 0.0, 0) PORT_SENSITIVITY(25) PORT_INVERT PORT_KEYDELTA(7) PORT_PLAYER(2)
 
 	PORT_START("UNUSED")
 	PORT_BIT( 0xff, IP_ACTIVE_LOW, IPT_UNUSED )