PapiStep is a very addicting casual game for the Mac. There are versions for the iPhone and other iOS devices as well. The premise of the game is rather simple. You control Mr. Papi, and you have to jump from platform to platform without falling. Every time you land on a platform, you stick to it, so you won't slide to either side. The platforms move to the right and the left, but you won't lose if you go over to either side, you will simply appear on the other side.
The challenge of the game lies on the fact that the platforms are smaller and smaller as you go up. They also move at different speeds and are at different distances between each other. If you are patient and calculate your moves, the game isn't really hard at first. Of course, once you go over 1000 points, then the game is really challenging. When you lose, you can share your score on the leaderboard or restart the game.
All in all, this game is very simple and it has very basic graphics. It is a casual game and you have to understand that. For a free game, PapiStep is very addictive, challenging and fun.