Super unique and interesting game. I had a blast designing my guns. It's clear that a lot of thought went into figuring the customization out and it shows - everything with that section is rock solid and I can offer no feedback that I think would improve it, just add more modifiers.
I found a couple of issues with other aspects:
-The damage sound is much louder compared to the fire sound, it was a bit annoying. It kinda makes sense since you want to alert the player, but it could get toned down a bit
-Lack of an options menu hurts , especially considering how nice and thoughtful the customization UI is
-The player projectile are homing - maybe as a result of a modifier that I missed, but what ended up happening is I would just spin in circles and not control my ship's orientation, since the missiles would go for the nearest ship. I think that takes away a skill portion (aiming) from the game
-Difficulty curves - for me the hardest part was as soon as the enemies spawn, since you'll most likely be surrounded. The level then becomes much easier if I survive the first second or so of the wave.
-Sometimes the ship wouldn't be distinct enough from the background or surrounding enemies (or both) and I'd lose sight of it. Might be an issue on my end more than anything since it's late at night and I'm blind as fuck
Everything else is stellar, especially the nice presentation with the backgrounds and enemy design
Final score: Need a techno soundtrack and you've got a winner / 10