At first, it was a little tricky to understand the goal, but once I got it, the game was a little too easy for me. It might have been more fun if the line wasn't there and the player had to use their judgement to make sure they wouldn't die, and/or add some different obstacles that do different things, like walls, or something that slows or speeds a character, etc.
That being said, I love the art, and the concept is pretty interesting.