This was a really cool concept, I love what you did here!
A few player experience issues:
I couldn't see the health bar on my screen and my initial thought was the bottom bar was my screen. So I guess: increase visibility on health bar and include a way of showing damage done to the machine that's more than just reducing the bar (you might look at fighting game health bars for ideas here).
A few iconic pieces for this style of game that I was looking for and didn't see: A pickup to improve damage output and some of the attacks coming toward you being destroyable.
Overall, I really enjoyed it :) I just assume we're all doing a gamejam to potentially improve our work, so I try to share a few thoughts on improvements!