Really liked the short levels, the music and the time shift mechanic. The visuals and aesthetics are very polished, and overall I had a lot of fun.
On the other hand, I wish there was a pause menu and a death screen (if there was and I didn't see it, I apologize in advance). Have I not read the comment about R restarting the level, I would not have played it to the end. I felt the combat was laking a bit of juice too, something like enemy hit flash would really help to show enemies are actually taking damage. Also, after defeating the final boss nothing happened. I think there was an exit on the top left of the arena that should have openned, but it didn't.
Overall, great work with the visuals, level design and concept! This is a very solid game :)