A classic Tower Defense style game. Strategy and tactics are paramount in this game. Place your units in key positions to defend your Castle. You have a huge variety of units to play with. Mario, Luigi, Princess, Toad, Poison Toad, Mega Plant, Fire Mario & Luigi, etc, etc. Each unit offers unique abilities that will help you stave off the hordes of enemies that come at you. Keep in mind that all units (except Lightning Cloud) must be placed in the rocky areas. Buy, upgrade, and research using coins.