Checkpoint is a game released in Spring 2011, in which you are simply a stick figure sent to conquer puzzles. It is a platformer where you must solve the aforementioned puzzles to reach checkpoints, hence the name of this game. When you die you return to a checkpoint, and there are indeed MANY ways to die! But sometimes, death is necessary to move on, through the use of crafting your corpses into a bridge, and feeding a monster to get a key, among other sadistically-amusing things. Levels are randomized before you play, so there is a different playthrough every time, but as you proceed onwards, the levels become increasingly more difficult. It can be played here !
In the game, you will mainly use the arrow keys to move your hero around. However, this doesn't mean that all you can do is run and jump. You can also kick off of walls (a popular Super Mario move, termed "Wall Jump"), crouch and slide under tight crevices, and more minor things.