Creep waves could be updated a bit, by having more different types of waves and force you to make a stratgy (preferably many different ones would work). The difficulty scale to quick in the end, the money doesnt scale at the same pace. Hope you find some useful ideas, I know some are rather obvious though...
nice game, defenatly got potential if you keep improving it! Here are some suggestions.
Towers could be a bit more different, so you can make different tactics. the first tower in the list (orange/red) is very simular to the third (purple/pink). There is no tower that shoot many monsters at once, either by shooting many bullets or by shooting bouncing bullets that jump from monster to monster. Also a AOE tower (area of effect) tower could be nice, either by shooting projectiles with a splash radius or by having a radious around the tower that hits all monsters in it. It would be nice if you wrote out how much poison damage the poison tower does, and how many % the slow tower slows. Also if it doesn't already, you could make the slow tower slow more % each time its upgraded and same for the poison tower, increase its effect. Also I think you should give the towers names, eg slow tower, rapid tower, poison tower, etc.
posted already but since ppl are to lazy to go back, A: Save the man, get fish for the fishermen, and keep the sharks away from the child. B: Let the sharks eat the child. C: Die from the army raft (mines). D: Die from submarine (torpedoes). E: Destroy the submarine. (Taken from Gymboy7 comment)
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