Really nice game!
The animations and the environments are so well made!
It was fun to kite the zombies around the city, and the titan is pretty cool!
You already know this, but some satisfying sound effects would really add a lot more polish to this game.
The only other point of feedback I could give is that, on my second run, it felt a little weird that the first weapon available to me was the rocket launcher for 2k. If random weapon spawns are necessary, maybe limiting what kind of weapons appear in spawn could be a good idea.
Other than that, it's a very solid game. Nice job!