The keys:

• Left: Move left
• Right: Move right
• Up: Move up
• Down: Move down
• Ctrl or Z or Y: Button 1
• Alt or X: Button 2
• 1: 1 Player start
• 2: 2 Player start
• 3: Insert coin (slot 1)
• 4: Insert coin (slot 2)
• 5: Insert coin (slot 3)
• Keypad +: Increase frame skipping rate
• Keypad -: Decrease frame skipping rate