Keys:
Arrow up or space - Fire
Arrow down or M - Fire a missile
P - Pause on/off
S - Start the game
Left arrow - Move spaceship to the left
Right arrow - Move spaceship to the right
Escape - End the game currently playing

Instructions/rules
If the attacking spaceships comes all the way down to your spaceship you lose two life
Bonus life every 10000 points
When the UFO passes - try to hit it, when you do you gain 1000 points and a new missile
500 points for completing each level
The attacking spaceships may have one more bullet on the screen for each level, the game also moves faster
You may have 6 bullets on the screen at any time (and only one missile)