I loved this. It's got a nice retro pixelart style, which with the music put me in mind of early DOS or the Megadrive. It was simple to pick up but still pretty addictive; I ended up finishing the whole thing (which I was not expecting as I'm generally awful at boss battles).
I also really liked how you included the mech pilot aspect. That's something I'd originally hoped to include on mine as well, but ran out of time. It's done really nicely here, with the avatar on the UI and customised paint schemes.