if you've played bloons tower defense 4 than you know what I'm talking about so to play open up a new tab and go to this site http://ninjakiwi.com/Games/Tower-Defense/Play/Bloons-Tower-Defense-4.html start bloons tower defense 4 and go to sandbox mode go back to my project and hit the next challenge button you can only use the towers in the list, you can only use the number of towers listed by the variables same with the upgrades, the list on the right will tell you what bloons to send out
