Cool game, I liked the visuals and sfx, the music made me feel like I was going a little mad but no big deal.
Gameplay wise, it definitely works, but with more time and balance it would feel a lot better. The upgrade cost scaling was the most questionable part for me, going from very cheap to unaffordable and back. At one point they were even costing negative money when I was deep in the negative, so I assume they scale in some way off your current total, but this could definitely be a bit more sane.
Overall a solid entry and a fun game, which is a win.