I choose to start with the tutorial, but still couldn't figure out how to place towers. It might be nice if that was made more apparent in the tutorial stage. I also think I hit either a bug, or a serious lag when I went out to face the enemies, the whole game was frozen for probably a good 10 seconds. I like the idea of playing along with your troops to defend a tower but would have enjoy this more with clearer explanations of how to do things.