Going into this I was thinking two things:
"Oh I guess making a shmup in 72 hours is pretty cool" "Wait how does this have anything to do with looping?"
Well, you definitely managed to fool me, this was pretty sick! The music slowing down, the rewind, the explosions of your clones, it was great! There's just a few points I want to point out:
-Like Quinn mentioned, your clones aren't really that helpful, because when they die, you're immediately in hot waters again. Maybe it would be cool if, instead of starting out with them, you could spawn them when you need them! Might not keep in line with the theme as well, but it'd benefit the gameplay heaps! (Definitely cause the game is hard and I'm bad at shmups.)
-The background was a bit too busy. It was kind of distracting and the simple sprites moving over the complex background made it harder for me to focus.
But, I'm not gonna lie. Damn dude, that was pretty awesome!