Really really good. The use of the theme was on point and fun as hell, the bosses were fantastically designed. I really really liked decking myself out and I appreciated that where I put things mattered. The writing was also really funny. Art was also great.
I did feel a little overwhelmed in fights though; the camera angle is a bit too low and bosses are hard to follow, especially with the amount happening on screen and loud sounds when the player shoots.
All in all though it was really incredible especially for the time frame it was built in. Amazing job!