diff --git a/src/mame/drivers/rotaryf.c b/src/mame/drivers/rotaryf.c
index 2a86ba66e63..3919d803625 100644
--- a/src/mame/drivers/rotaryf.c
+++ b/src/mame/drivers/rotaryf.c
@@ -24,14 +24,36 @@ public:
 		m_maincpu(*this,"maincpu"),
 		m_videoram(*this, "videoram"){ }
 
+	DECLARE_READ8_MEMBER(port29_r);
+	DECLARE_WRITE8_MEMBER(port28_w);
+	DECLARE_WRITE8_MEMBER(port30_w);
+	bool m_flipscreen;
 	required_device<cpu_device> m_maincpu;
 	required_shared_ptr<UINT8> m_videoram;
 	UINT32 screen_update_rotaryf(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect);
 	TIMER_DEVICE_CALLBACK_MEMBER(rotaryf_interrupt);
 };
 
+READ8_MEMBER( rotaryf_state::port29_r )
+{
+	UINT8 data = ioport("INPUTS")->read();
 
+	if (m_flipscreen) return data;
 
+	return (data & 0xCD) | ((data & 0x01) << 1) | ((data & 0x0c) << 2);
+}
+
+WRITE8_MEMBER( rotaryf_state::port28_w )
+{
+// sound
+}
+
+WRITE8_MEMBER( rotaryf_state::port30_w )
+{
+	/* bit 0 = player 2 is playing */
+
+	m_flipscreen = BIT(data, 0) & BIT(ioport("COCKTAIL")->read(), 0);
+}
 
 
 
@@ -65,22 +87,25 @@ TIMER_DEVICE_CALLBACK_MEMBER(rotaryf_state::rotaryf_interrupt)
 UINT32 rotaryf_state::screen_update_rotaryf(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect)
 {
 	offs_t offs;
+	pen_t pens[2];
+	pens[0] = RGB_BLACK;
+	pens[1] = RGB_WHITE;
+	UINT8 i,x,y,data;
 
 	for (offs = 0; offs < m_videoram.bytes(); offs++)
 	{
-		int i;
-
-		UINT8 x = offs << 3;
-		int y = offs >> 5;
-		UINT8 data = m_videoram[offs];
+		x = offs << 3;
+		y = offs >> 5;
+		data = m_videoram[offs];
 
 		for (i = 0; i < 8; i++)
 		{
-			pen_t pen = (data & 0x01) ? RGB_WHITE : RGB_BLACK;
-			bitmap.pix32(y, x) = pen;
+			if (m_flipscreen)
+				bitmap.pix32(255-y, 247-(x|i)) = pens[data & 1];
+			else
+				bitmap.pix32(y, x|i) = pens[data & 1];
 
-			data = data >> 1;
-			x = x + 1;
+			data >>= 1;
 		}
 	}
 
@@ -95,28 +120,27 @@ static ADDRESS_MAP_START( rotaryf_map, AS_PROGRAM, 8, rotaryf_state )
 //  AM_RANGE(0x6fff, 0x6fff) AM_READ_LEGACY(random_r) ??
 	AM_RANGE(0x7000, 0x73ff) AM_RAM // clears to 1ff ?
 	AM_RANGE(0x8000, 0x9fff) AM_MIRROR(0x4000) AM_RAM AM_SHARE("videoram")
-	AM_RANGE(0xa000, 0xa1ff) AM_RAM
+	AM_RANGE(0xa000, 0xa1ff) AM_RAM	/* writes 00, 18, 27, 3C, 7E, FE to A019, A039, A059... A179 */
 ADDRESS_MAP_END
 
 static ADDRESS_MAP_START( rotaryf_io_map, AS_IO, 8, rotaryf_state )
-//  AM_RANGE(0x00, 0x00) AM_READ_PORT("UNK")
 	AM_RANGE(0x21, 0x21) AM_READ_PORT("COIN")
 	AM_RANGE(0x26, 0x26) AM_READ_PORT("DSW")
-	AM_RANGE(0x29, 0x29) AM_READ_PORT("INPUTS")
+	AM_RANGE(0x29, 0x29) AM_READ(port29_r)
+
+	AM_RANGE(0x02, 0x02) AM_WRITENOP
+	AM_RANGE(0x04, 0x04) AM_WRITENOP
+	AM_RANGE(0x07, 0x07) AM_WRITENOP
+	AM_RANGE(0x20, 0x20) AM_WRITENOP
+	AM_RANGE(0x21, 0x21) AM_WRITENOP
+	AM_RANGE(0x28, 0x28) AM_WRITE(port28_w)
+	AM_RANGE(0x2a, 0x2a) AM_WRITENOP
+	AM_RANGE(0x2b, 0x2b) AM_WRITENOP
+	AM_RANGE(0x30, 0x30) AM_WRITE(port30_w)
 ADDRESS_MAP_END
 
 
 static INPUT_PORTS_START( rotaryf )
-	PORT_START("UNK")
-	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_UNKNOWN )
-	PORT_BIT( 0x02, IP_ACTIVE_HIGH, IPT_UNKNOWN )
-	PORT_BIT( 0x04, IP_ACTIVE_HIGH, IPT_UNKNOWN )
-	PORT_BIT( 0x08, IP_ACTIVE_HIGH, IPT_UNKNOWN )
-	PORT_BIT( 0x10, IP_ACTIVE_HIGH, IPT_UNKNOWN )
-	PORT_BIT( 0x20, IP_ACTIVE_HIGH, IPT_UNKNOWN )
-	PORT_BIT( 0x40, IP_ACTIVE_HIGH, IPT_UNKNOWN )
-	PORT_BIT( 0x80, IP_ACTIVE_HIGH, IPT_UNKNOWN )
-
 	PORT_START("COIN")
 	PORT_BIT( 0x20, IP_ACTIVE_HIGH, IPT_COIN1 ) PORT_IMPULSE(1)