Aquaventure

The player must dive to the bottom of an undersea cavern and retrieve a fabulous treasure. Along the way they must avoid fish, sea horses, and other underwater creatures attempting to block their path. The diver is armed with a spear gun which he can use to temporarily kill one of the creatures. However, each enemy they kill is soon replaced by a faster and indestructible version of itself, so they need to carefully carve a path to the bottom only destroying the creatures that get in their way. After retrieving the treasure and returning it to the top of the cavern, a mermaid will appear. Touching the mermaid will take them to the next level, where they get to do it all over again. At the top of the screen there is a turtle, which shows how much air is left. If the turtle reaches the Air sign at the far end of the screen before completing the level a life is lost.