I guess the game is endless, I stopped after wave 30 as I was only getting the same lonely boss fight for a while.
The game is very fun. I love this kind of art and you really nailed it, and the music is super nice too. The scope of the gameplay isn't huge but I think what's there is pretty solid, it took me a couple of tries to apprehend and finally handle it, it's just a little bit weird that it ends in such a loop but before that the difficulty is quite perfect for my taste.
I wish RMB allowed to use the secondary fire.
This is a super cool entry, thanks for sharing.