An Okay Game
First of all the engine is solid, keep that but definatley rework the game. It was slow paced, maybe slow framerate, no effects or blood or anything and the way zombies just dissapeared was also quite anti climatic. The no health bars over there heads unlike in many TDs could have been to add difficulty, but I assume it was a lack of coding skill. Next, the maps were confusing as hell, there was a lot of detail, like extra things, which is great sometimes, i really see effort in this but it didn't stand out, it looked like the zombies were walking through a scrapyard it was literally littered with extras that distract you. And lastly some poor descisions feelingwise ruined the zombie effect. If you wanted to get across desperation and horror, maybe make the towers dudes with guns not giant automatic turrets labled submachine gun but clearly work a hell of a lot moe like a slow firing nerf gun, cause SMGs supposed to be fast firing... Anyway game wasn't too fun but it's a learnin expirience, make some changes and it can be much much better.