Unlimited mana.
Your mission in this combination of strategy and RPG game is to build towers, traps, walls and place into gems with different properties to stop the waves of invading creatures. Combine gems to create powerful defense towers and defeat the critters. Different colors have different abilities in addition to dealing damage; cyan gems have a chance to slow enemy progress, for example, while yellow gems have a chance to deal multiplied damage.
Use YOUR MOUSE to click on spell buttons, click to place buildings, drag gems to where you need them. Good luck!