the best way to win is to ignore the enemy and have a constant stream of swords men at all time in one line. i have beat several 69 difficulty levels with this.
the girls are the easiest to lvl. just chase enemies to one side of the river and have your girls on the other and have them kill from a distance they can go us to 30 in one week.
the best td i ever played. i.t is actually worth it to upgrade things and buy better quality towers. the bosses are a bit too hard, but still it is awesome.
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