best strat I got, is only buy machine guns, 2 per floor, and 1 laser per floor, on the off level (the ones you don't have to buy a new elevator, lvl up a turret, by the time you get to the end, you should have lvl 3 in each machine gun and laser, and never have to click to fire after lvl 3
if you wish to know the location of all of the sub-treasures then farm the location 19-19 until you get all of the locations revealed, after that good luck.
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