Good idea; we need to stay focused on every boat at the same time, and the difficulty increases with time. It's a good little arcade game. You could make the animation smoother by adding more frames to the boats. Also, you could add a little "guide" or "how to play" before launching the game when we set play. The artworks can be upgraded, but it's already good for a 48h game. Maybe, having a scoreboard at the end of or the best score would be a good addition.