This is really well made, I love the little effects, in particular the flamey stuff on the sidebars. Sadly I couldn't beat the game because it was really hard, managed to get up to the midboss and that's it (I'm not actually good at these games).
I don't understand the true purpose of the rewind mechanic. Ultimately, it lets you retry individual segments but it doesn't provide much of an advantage compared to e.g. having multiple lives. Maybe I didn't understand how it works.
I would really like to see a devlog on this, particularly regarding the rewind mechanic. I can't imagine how that was implemented.
You should join the Shmups Discord, lots of shmup devs there.