What is the difference between towers and scavengers? It would be interesting:
- to have scavengers increase your income but low def/attack,
- have energy supply buildings
- have limited building area that expands with certain buildings (compare the pylons in starcraft)
- have ammunition for the towers that has to be manufactured in specialized buildings
- to actually see what an upgrade does
- to actually see how the zombies are getting stronger / faster with each wave (compare gemcraft labyrinth here on newgrounds, the bar on the left side)
- to be able to build only during day, depending on your amount of civilians building something could take multiple days
- to be able to rescue civilians during the day for population increase
- to start only with a small group of civilians or only 1 civilian (yourself)
- have dispensible units (landmines which cost only 1 - 5 cash but are destroyed after usage)
"It s a turret defense, why does it need story?"
Creating characters and letting some of them die/romance etc. will give you the opportunity to increase the replayability of the game. "This time, I will not let girl #4 die."
music is too silent (I hear it aat pprox 1-5%, I dont hear any sound.)
clicking and dragging should move the terrain when zoomed in (that is what you are currently having to use wasd for)
That´s all for now, but I bet you have many more ideas to not let this become another 3/5 play-once-and-never-again game.