pulse emitter is too good. will beat impossible without losing any lives if you simply fill the map with them. after the map is full, start upgrading the center ones to level 3 (75 gold and +5 to the tower count). eventually, you'll have 700+ or so tower count. the level 1 towers will do ~30-710 or more.
This game has very bad AI issues. your towers shoot stuff closer to the start of the maze, rather than the finish. The way towers lose/gain range and AIR/LAND as they level up, also ruins it for me. It's hard to plan, unless you study the tower level charts. Despite these problems, some good ideas are here. 3/5.
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