The only critique I can add is that it seems some upgrades are not worth it. For example, the eye tower gets a FAR bigger boost for the first upgrade (for $45) than from the second upgrade ($90). You're much better off with three level 2 eye towers for $450 than 2 level 3 eye towers for $500. The critical tower seems overpowered when fully upgraded...quick enough fire rate, huge range, and powerful enough to even kill the "brown" resistant monsters (unlike the other two types). For fire towers, the power jump from a level 3 basic fire tower to level 1 inferno tower is incredible - damage is increased 2.5x and the fire rate barely drops at all, plus the fire damage over time bonus. Sure you could upgrade it after that...but I'm not convinced the upgrades are better, much less a good use of your money. So some tweaking with the power levels of certain towers at certain upgrade levels is probably a good idea, but for a new game that's to be expected. 5/5 for potential.
I can't get the achievement "Go over your current maximum speed" for $1500. Is it bugged? To be clear, I've gone over my previous maximum speed numerous times...or does it mean the maximum speed I'm supposed to be able to go based on stats?
 "Learn to Fly 3"){kind=icon}
 "Monsters TD"){kind=icon}
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