Solid entry! I love the double jump animation! The graphics are clean and the audio is good! I think there could be more visual feedback for when you hit an enemy or die. For example, a death animation (Although my game doesn't have that lol). Also it would be more fun if the player didn't die in 1 hit. Maybe 2 or 3 hits would be nicely balanced.
As for the bullets, I think the rewind mechanic was a bit useless, since most of the time my bullets would hit a wall, so rewinding them wasn't possible. It also doesn't seem necessary to beat levels.
Overall though, you did a good job! The game is fun and movement felt good! One thing you could do is increase the timescale a bit! It can make the game faster and usually, more fun!