Ecco swims through horizontally scrolling stages, using momentum, vertical movement, sonar, and his damaging head-butt attack. Sonar reveals information, activates certain objects, and helps locate routes or interact with the environment. Air is limited, so finding the surface, air vents, or other sources of oxygen is an essential part of exploration.

Stages mix navigation, puzzle solving, enemy encounters, and timed movement. Progress depends on learning marine environments, locating passages, protecting allies, and acquiring abilities or information that open later routes. The adventure is primarily a single-player campaign rather than a collection of separate competitive modes.

Treat sonar as an exploration tool rather than merely an attack-related ability. Use it frequently near walls, objects, and apparently empty sections of water, because important routes and interactions are often not obvious.

Manage air before pursuing enemies or collectibles. Learn the safest paths through each area, use momentum to cross dangerous spaces, and avoid unnecessary fights when a stage is primarily a navigation puzzle.