I loooove TD games, LOVE them, so it pains me that this one is very difficult to play. Making it to the third round was by the skin of my teeth, and I feel like it's less about playing the way you want with towers you like and more about figuring out the puzzle of which towers you need for each round. That could be design intent, and it's a bold statement if so, otherwise I think you need more money and buffed towers.