sub-rescue
This is a subaquatic shoot-em-up for the Sega Master System. It is heavily inspired by SeaQuest for the Atari 2600.
In this game, you have to use your submarine to rescue the divers, while fighting off enemy submarines and sharks.
Keep an eye on your oxygen gauge: if it depletes, you lose a life; climb your submarine all the way up in order to fill your oxygen.
Once you have collected 6 divers, climb your submarine all the way up in order to go to the next level.