I can't tell if this is a positive or negative review lol
The iteration is part of the design; you're supposed to see what works, and when you lose you make up for what you don't have by making new towers. I understand if that's not for everybody.
As for the "obtuse" nature of the game, I plan on adding more clarifications on mechanics at some point. I apologize for not explaining much.
If you want to upgrade towers, you have to select the tower and select an upgrade. You can only have one upgrade on each tower. I think the speed upgrade is bugged right now, but I'm working on a patch.
Also I thought the insider trading mechanic was funny so I added it.
Thanks for playing!