Attempting to set 'Escape' as a button for config exits the game. Probably best to let the player know if that's a reserved key.
Shooting controls were a bit confusing, as I'm sure you've heard many times before. I get that there's benefits to not firing, but they hardly felt worth it and I'd much rather have auto-fire so as to not kill my fingers. The bomb key didn't seem to do anything and the focus key did... something I never figured out, probably a projectile barrier but I think I saw it drain two bars instead of 1.
The level was fast but it wasn't all too difficult aside from a moment or two of tight bullet patterns. I never beat the boss, though, that form where they shoot aimed attacks and can't be hurt until you pop the bubble got me every time.