Now I'm playing with POWER!
This an epic showdown! The nightmarish weapons of the Wehrmacht against the genius of Nikola Tesla!
The pace is good, just enough to keep you on your toes but not enough to unfairly overwhelm.
I agree, there needs to be a little more. Whether it be upgrades or abilities, there just needs to be more for the player to buy. After round 17I've bought pretty much everything and just play through the rest of the game only having to worry about money for my health. What you might consider is having just enough upgrades and powers that the player cannot buy them all, leading to a customizable experience different for every player.
The visual approach is a nice touch. It looks like a mix between Soviet propaganda, comic books, and a German Expressionist film. Your war-torn apocalyptic setting looks like the sets from the film Cabinet of Dr. Caligari if it had more order to it.
I have to give special points for the music; it's just phenomenal! It FEELS like I'm the legendary Man of Lightning himself fighting back the Third Reich! The title music is my favorite and I've actually been listening to that while typing this.
This has caught my interest, and I eagerly await more games!
Might I ask about the music? I'm having remarkable difficulty finding those you credited. I WANT this music!