Surprisingly deep game! I like the enemy variety and the "help" (Gradius-like Option). Really adds an interesting layer to an otherwise simple concept.
I appreciate the way the rotation works. It took a few moments to get used to but I like it a lot more than something like Asteroids - no inertia lets you be a lot more intentional with how you're navigating all the bullets/enemies. Also, the persistence of upgrades between playthroughs/game launches is really nice.
The button map is a little bit awkward and I found myself pretty unsure of what button was what in the menu. E.g. the rotation button, which I'm holding for a decent amount of the game, suddenly sets me to the exit/negative menu option.
Otherwise, really neat game!