Honestly, I like the idea of the game. However, it seems kinda pay-to-win imo. Currently, I'm stuck at 2-5, which is nearly impossible despite having upgraded weapons and a nearly maxed out mech. The closest I've gotten is the boss at 100%, but the hordes of zombies tend to block most of the enclosed arena. Also, the game tends to get laggy when zombie hordes spawn, which really doesn't help. Overall, the game itself is fun, but seems to have balancing issues that makes it seem pay-to-win.

While I do enjoy the game, I can't give it five stars due to how the game slows to a crawl whenever a zombie wave starts. When a wave starts, after a few moments, there are just too many moving objects (the zombies) on the screen which causes the game to slow down and the problem is even worse if you didn't collect the exp items that drop since that adds more objects to the screen also projectiles from weapons can also cause the game to slow down.

It starts out ok but by the time you get to stage 2-2 it becomes ridiculous. You get swarmed and the frame rate drops to the point of almost freezing yet the zombies are just fine. The time between attacks are entirely too long and it takes the fun out of it. I'm sure if you dump a bunch of money into it, it would help. As with most mobile games it's definitely pay to win. If the time between attacks were cut in half it would be a lot better