Salt

This game has you tapping the space bar in rhythm to simulate swimming. As you continue to swim, the game's story progresses. If you stop swimming, you get an alternate version of the story. By progressing between swimming and not swimming, you finish the story.

It's a magical realism story centered on one moment in time, as you swim from one beach to another. I found it effective, but the interactivity wasn't quite what I liked.