Pirates of Teelonians is a defense game similar to Plants vs. Zombies. Before you begin each battle, you will have to select a captain. One captain is available to you at the start of the game; the other two captains can be unlocked by completing levels. You can also choose units that you have unlocked and buy power-ups prior to each battle. Battles consist of you controlling your captain and placing units to kill enemy pirates that travel along five paths. You can move your captain from path to path and use his special abilities to kill enemies. Slain enemies will sometimes drop gold or power-ups, which can be collected with your mouse. Place power-ups on your units to ehance them temporarily.