challenge : after wave 20 (21,22,etc) can only place thorn stick thingies and use buffs. after wave 26 (27,28,etc) can not place / replace towers, and can not use buffs.
Thanks for letting us know it's really endless, I got till wave 30 (hard difficulty) but then it was just going AFK for rounds, and then replanting few of the rocket plants and hedges which protect my tulips
