heres a way to get unlimited mana; step 1. buy the tower step 2. build 2 of them so you will have all your building slots filled step 3. once all the towers are built try to make a 3rd and although you cant make one you will recieve 30 mana because the game is refnding mana that was never spent + to keep this comment alive
this is a good game but it would be cool if you could play a human campign when you beat the game and you would drop a cure on the zombies and instead of having the zombie slot have have the human slot