Board Thread:Questions and Answers/@comment-24217346-20180615153648

Perhaps the most important mechanic transition from BTD5 to keep in mind is once you buy 2 of the first 3 upgrades for any tower, the third one is closed already. (No way to get 1-1-1 or more)

Does this seem like a balance against the potential of OP towers or like a really confusing twist that could overstay its welcome or both? 