Evacuation is a neat and very addictive puzzle game. You need to purge your spaceship of its alien intruders. To do so, you can click on a door to open it. If it's an exterior door, anything inside that room will be sucked out into space.
Thing is, when you open one door, all doors of that colour will also open. So be careful you don't release aliens into the same room as your crew. Or cause your own men to be sucked out into space.