This game was definitely inspired by Call of Duty's zombie mode, correct? I only ever played that mode a few times as a kid at... probably one point in my life. Nevertheless, this game is surprisingly more resource intensive than what I was expecting! And the lack of graphic options does make me wonrry for weaker hardware! And my PC here is pretty high end!
Overall, a fun game (well, it is free~) for what it is. But does have multiple problems, such as progression, what there is to do, and whatnot.