The game looks really cool! Nice job on the blood splatters as well.
The jumping does feels a bit floaty though. You should probably increase the gravity. I usually start with 20 and sometimes even go up from there.
The camera is also really close. For the big jump in the level, I can't even see what I'm jumping over.
Also, I couldn't figure out how to rewind time. You should probably add an explanation of the controls to the description of your game.
I'd really appreciate it if you would have a look at my game as well, and be sure to download the smaller version :D