This is a very addictive adventure game. You can move between layers that make each level. As you switch between them, one will become the active layer while the other will become transparent and passable. It is all up to you to find out what you should do to get to the exit. Just be careful not to switch into solids. The game includes a level editor with which you can easily access hundreds of user-generated levels ranging from not so interesting to awesome and easy to the most difficult thing you have ever attempted in your life.