Really cool game, good job! It was pretty addicting, I played it for quite a while.
A couple of comments I had:
- I have no gripe with the level being hard, but it would be cool if the doppelganger persisted for more than just the next one life. Iow, if doppelganger would always be the "best" run you have completed overall instead of only the last run.
- I also ran into a bug where the avatar and the doppelganger were both OK, but the game still thought I died in spots
Overall I love the idea of a running game like this