diff --git a/src/mame/drivers/astrocde.c b/src/mame/drivers/astrocde.c
index 96bb1dc135e..8eb3d30bb47 100644
--- a/src/mame/drivers/astrocde.c
+++ b/src/mame/drivers/astrocde.c
@@ -104,6 +104,7 @@
     DIP locations verified for:
     - seawolf2 (manual)
     - wow (manual)
+    - spacezap (manual)
     - gorf (manual)
     - robby (manual)
     - profpac (manual)
@@ -119,6 +120,7 @@
 #include "sound/samples.h"
 #include "sound/astrocde.h"
 #include "sound/ay8910.h"
+
 #include "tenpindx.lh"
 #include "gorf.lh"
 
@@ -835,7 +837,7 @@ INPUT_PORTS_END
 
 static INPUT_PORTS_START( spacezap )
 	PORT_START("P1HANDLE")
-	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_COIN1 )
+	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_COIN1 )	// manual says this dip is unused on cocktail cabs
 	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_COIN2 )
 	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_TILT )
 	PORT_SERVICE( 0x08, IP_ACTIVE_LOW )
@@ -844,19 +846,19 @@ static INPUT_PORTS_START( spacezap )
 	PORT_BIT( 0xc0, IP_ACTIVE_LOW, IPT_UNUSED )
 
 	PORT_START("P2HANDLE")
-	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_JOYSTICK_UP ) PORT_4WAY PORT_COCKTAIL
-	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_JOYSTICK_DOWN ) PORT_4WAY PORT_COCKTAIL
-	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_JOYSTICK_LEFT ) PORT_4WAY PORT_COCKTAIL
-	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_JOYSTICK_RIGHT ) PORT_4WAY PORT_COCKTAIL
+	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_BUTTON2 ) PORT_COCKTAIL PORT_NAME("P2 Aim Up")
+	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_BUTTON3 ) PORT_COCKTAIL PORT_NAME("P2 Aim Down")
+	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_BUTTON4 ) PORT_COCKTAIL PORT_NAME("P2 Aim Left")
+	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_BUTTON5 ) PORT_COCKTAIL PORT_NAME("P2 Aim Right")
 	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_BUTTON1 ) PORT_COCKTAIL
 	PORT_DIPUNUSED_DIPLOC( 0x20, 0x20, "JU:1" )
 	PORT_BIT( 0xc0, IP_ACTIVE_LOW, IPT_UNUSED )
 
 	PORT_START("P3HANDLE")
-	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_JOYSTICK_UP ) PORT_4WAY
-	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_JOYSTICK_DOWN ) PORT_4WAY
-	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_JOYSTICK_LEFT ) PORT_4WAY
-	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_JOYSTICK_RIGHT ) PORT_4WAY
+	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_BUTTON2 ) PORT_NAME("P1 Aim Up") PORT_CODE(KEYCODE_UP)
+	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_BUTTON3 ) PORT_NAME("P1 Aim Down") PORT_CODE(KEYCODE_DOWN)
+	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_BUTTON4 ) PORT_NAME("P1 Aim Left") PORT_CODE(KEYCODE_LEFT)
+	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_BUTTON5 ) PORT_NAME("P1 Aim Right") PORT_CODE(KEYCODE_RIGHT)
 	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_BUTTON1 )
 	PORT_DIPNAME( 0x20, 0x20, DEF_STR( Cabinet ) )	PORT_DIPLOCATION("JU:2")
 	PORT_DIPSETTING(    0x20, DEF_STR( Upright ) )
@@ -1381,6 +1383,9 @@ static MACHINE_CONFIG_DERIVED( spacezap, astrocade_base )
 	MCFG_CPU_MODIFY("maincpu")
 	MCFG_CPU_PROGRAM_MAP(spacezap_map)
 	MCFG_CPU_IO_MAP(port_map_mono_pattern)
+
+	/* video hardware */
+	MCFG_PALETTE_INIT(astrocde_bw)
 MACHINE_CONFIG_END
 
 
@@ -1821,7 +1826,7 @@ GAME( 1978, seawolf2, 0,    seawolf2, seawolf2, seawolf2, ROT0,   "Midway", "Sea
 /* 91354 CPU board + 90700 game board + 91356 RAM board */
 GAME( 1980, ebases,   0,    ebases,   ebases,   ebases,   ROT0,   "Midway", "Extra Bases", GAME_SUPPORTS_SAVE )
 
-/* 91354 CPU board + 90706 game board + 91356 RAM board + 91355 pattern board */
+/* 91354 CPU board + 90706 game board + 91356 RAM board + 91355 pattern board. Has B/W monitor and color overlay */
 GAME( 1980, spacezap, 0,    spacezap, spacezap, spacezap, ROT0,   "Midway", "Space Zap", GAME_SUPPORTS_SAVE )
 
 /* 91354 CPU board + 90708 game board + 91356 RAM board + 91355 pattern board + 91397 memory board */
diff --git a/src/mame/includes/astrocde.h b/src/mame/includes/astrocde.h
index 65dc218384b..391ca44cd8f 100644
--- a/src/mame/includes/astrocde.h
+++ b/src/mame/includes/astrocde.h
@@ -27,6 +27,7 @@ extern UINT8 astrocade_video_config;
 extern UINT8 astrocade_sparkle[4];
 
 PALETTE_INIT( astrocde );
+PALETTE_INIT( astrocde_bw );
 PALETTE_INIT( profpac );
 
 VIDEO_START( astrocde );
diff --git a/src/mame/video/astrocde.c b/src/mame/video/astrocde.c
index 763e17d77a4..be0c0af9b84 100644
--- a/src/mame/video/astrocde.c
+++ b/src/mame/video/astrocde.c
@@ -167,6 +167,18 @@ PALETTE_INIT( astrocde )
 }
 
 
+PALETTE_INIT( astrocde_bw )
+{
+	int i;
+
+	PALETTE_INIT_CALL(astrocde);
+
+	// B/W: set whole palette to luma only
+	for (i = 16; i < 512; i++)
+		palette_set_color(machine, i, palette_get_color(machine, i & 15));
+}
+
+
 PALETTE_INIT( profpac )
 {
 	/* Professor Pac-Man uses a more standard 12-bit RGB palette layout */