Did you ever dream of appear in the zero gravity? The spaceship was crashed and now you are supposed to evacuate spacemen avoiding different dangers, such as swamping holes, hungry aliens, sharp spikes, blowing fans, etc..
Close the holes with your mouse from the spaceman's side to save him from sucking. Try to keep a distance from the aliens which move in a random direction.
Be aware of the spikes which can destroy the spaceman in a moment.