1/5 the game is too easy at first, but once towards the end, it gets ridiculously hard and impossible to beat. I had the whole screen covered with the best fully upgraded towers plus fully upgraded slow and poison towers and the enemies were still not dying. Too many enemies that are too strong for all the towers. Sorry if I'm harsh, but you really need to work on the game and improve a lot of things.
P.S. When I got a gameover, the game restarted itself to the first level, but the wave that killed me in the previous game was still going on and I lost almost half of my lives. Definitely needs to be fixed.
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