Blue Marine Zone is the fourth Zone of Sonic Blast. As with other Zones in this game, Blue Marine consists of two standard Acts followed by a shorter third Act which contains the Zone's boss.
Blue Marine is a typical Ancient Ruins-themed level that is flooded with water, with very few places of dry land to catch a breather at. As with most water-based levels in the series, the player will drown if they stay in water for too long. If Sonic or Knuckles need air, the player can either get out of the water, get an air bubble or travel in the suction tubes.
The Zone as a whole is a giant maze with complex networks of suction tubes that transport Sonic or Knuckles to different parts of the aquatic labyrinth. There are also water currents, which the player generally has to avoid as most currents will wash them back to earlier sections. Some areas have buttons that control the water level, as well as bridges that collapse when crossed.
||It's time to get your feet wet! Explore the mysterious underwater ruins while searching for rings and things. When air gets low, a countdown begins - gulp the big air bubbles to replenish Sonic's oxygen before the countdown reaches zero.
— Sonic Blast US manual