As one of the crew of an inter-galactic mineral freighter, you have to carry out maintenance work on the superstructure us-ing a network of ladders.

But during your work you make an unwelcome discovery... you are not alone. The ship is being taken over by aliens who will kill everyone unless someone stops them. And that someone is you.

Your only weapon is your space shovel. And the only way to destroy the aliens is to dig holes in the ship so they fall through, then fill the holes. You just hope the falls are fatal. Just when you think you've wiped them out still more aliens appear. Whatever you do, don't panic...

You start with 2,000 units of oxygen which is supplemented with every alien you destroy.

Scoring varies according to the colour of the aliens and the difficulty in destroying them. Cyan aliens score 100, red 200 and white 300. Red aliens have to fall through two levels and white ones only perish when they have plunged through three levels.

Choice of keyboard or joystick operation. Use a joystick if you have one.