I loved the style of this game. Visually it was awesome and matched the stealth game like feel.
I thought the rewind mechanic was a pretty original take on the theme as well, and was pretty elegant. At first, I definitely struggled and shot myself a few times. Then I started thinking about the path the bullet would take back, and it felt pretty good to plan out an attack especially if I got multiple monsters at once. I like how time slows down as you rewind to make it pretty easy to connect the hit. I think I prefer not having an angle indicator so you have to think about the path.
I did get stuck in a wall a couple times which was my only major complaint.