The concept of this game is fairly simple, move the walls around to trap aliens into little rooms until they fall asleep and disappear. In practice, the aliens are flaky about entering the pre-completed rooms before you can trap them in there, and the wall movement is to some extent confusing. They pivot 90 degrees in the direction you push them. Sometimes I think I'm doing it right, but there is still a hole in the room. Or worse, sometimes I end up trapping myself in the room! If you do that, you lose a life immediately, no chance to try to escape.