Zool, a gremlin-like creature from another dimension, finds himself on Earth with one goal in mind: to become a Ninja. His journey takes him through six worlds, each divided into three stages, where he must defeat his enemies and prove his worth.
Zool is a fast-paced side-scrolling platformer where Zool can run, jump, climb walls, and shoot enemies. Power-ups are scattered across the levels to aid him in his quest, including life-spending hearts, smart bombs, shields, improved jumping ability, and a duplicate of himself called "twin" that mimics his actions.
The options menu allows players to adjust game settings such as difficulty level, game speed (twice), number of continues, and background music style (rock or funk).