Even though the game is simple, there are a few quick ways to make it better:
1. If the player falls off, we have to reload to play again. Using the same r to reset would help
2. Increasing the difficulty a bit
3. Making like 3 levels so there is some variety
4. The player seems blurry, but I'm pretty sure it is pixel art. I'm going to assume you didn't change some import settings like compression, or texture filter.
Overall, it's a very very simple level. It doesn't really have much content, but even adding a few more levels would make it better.