Look: The xp bar should give all the things when reaching maximum then starting from 0. the going back thing on xp bar sucks. This thing needs some animations and challenges. "Idle" isn't equal with "no player involved". player is passive involved, not active, but he is. Add some things like day and night to make it interesting, some bad ass music which the player can listen while chatting/ doing something else. Also, some mini games if the player gets bored of being idle would be good. that's all for now. Also, use more colors :)
You must put towers near the enemy base to win. This is an offensive tower defense game ;) In later levels this becomes much harder because enemies have their own defensive towers. Did you play past level 3?
ok thanks I'm new to this video game thing..how do you update it?