Marine Adventure is an underwater shooter, pitting your diver against the evil and cunning fishies (and occasional whale or whatever that's supposed to be). Defeat the blue screen enemies and you are rewarded with a surprisingly different selection of enemies on the black screen, so that's definitely a plus in terms of variety.

A play straight from the Atari 2600 library, the in-game graphics don't match the vivid fantastical artwork on the box, but at least grown-up me doesn't get disappointed about this!