Canabalt is a fast, forced-side-scrolling platformer in which the player/character runs from left to right and has to avoid ravines and obstacles.
What makes it interesting is:
1. the only control the player has is to jump, using one button. You can't stop your character running. If you don't jump at the right moment, you die.
2. Despite this, the game works very well. The interaction is minimalist rather than minimal - the player needs to pay close attention and time the jumps carefully. The sound, graphics and overall design are beautiful, and are probably what makes this game. Rendered in blocky 3x3 pixel greyscale, the world your character is running through feels deep and atmospheric, and full of cleverly-realised details such as glass windows that smash and scatter debris when the character plunges through them, or flocks of birds that take to the air when startled. The sheer style, plus the fact the landscape is procedurally-generated, make this game very replayable.
All in all a tight, well-honed concept, beautifully realised.