You are a lone outsider in a strange, non-Euclidean world. As a Rogue, your goal is to collect as many treasures as possible. However, collecting treasures attracts dangerous monsters (on the other hand, killing the monsters allows more treasures to be generated). You can kill most monsters by moving into them. Similarly, if the monster was next to you at the end of your turn, it would kill you. The game protects you from getting yourself killed accidentally by ignoring moves which lead to instant death (similar to the check rule from Chess).