I always liked this one - the diving for gold seeming quite simply on Level 1 when there were only fish to avoid, but once the bombers, missles, electric fences and suchlike entered, the fight for underwater survival became increasinly desparate. If that wasn't enough, there's a time limit and limited oxygen. The difficulty ramped up at just the right rate, sound and graphics pretty good for the time - a good showing all round.
Ah, one of the first games I played on my Atari 800XL. Not a bad game by all accounts. On loadng the game you were presented with a jolly little ditty and then it's off to retrieve gold bars from the ocean floor.
Seemed easy enough, dodge the shoal of fish, grab the gold, then get back to your ship before the oxygen ran out. But of course, things are never that simple. Soon there were electric fields to avoid, giant black squids, helicopters dropping bombs, and the dreaded seabed missiles. Oh and of course there was the leach, always trying to suck the air from your tanks. As the levels went on, the challenge got harder as several of obstacles had to be avoided at once.
Great fun and quite challenging. Not the best graphics or sound, but for the time, a decent enough game.