Pretty good
I liked it, but there were a few issues I had:
1. The song was really annoying
2. If you fall from high enough you can pick up enough speed to fall through the ground, so you need to either cap the speed or have more collision tests
3. It would be cooler if something actually happened when u hit spikes, rather than just resetting
4. It could have used a bit more colour
But otherwise, nice job, and a good idea.