This is a game for those with sub-aquatic tastes and a great deal of time on their hands.
The snorkel you'll need because it's an underwater zap; the time because it's so difficult as to be almost unplayable.
The plot is attractive: not far from Neptune's Palace is an evil sea-serpent whose staple diet is sea-horse. It seems, though, that he prefers Neptune's luscious daughters. Your mission is obvious - get that monster.
You start off in the first cave facing deadly pink octopuses and the 'suckers' which guard the entrance to the next grotto. Your harpoon is an efficient weapon, but the movement of your frogman is so jerky that it's virtually impossible to avoid being punctured on the rocks or stung by an octopus.
Frustration is increased by the fact that wherever you die you always return to the first cave.
Eventually you just give up and forget about the amoeba swarms and monster crabs you've been promised. It's a pity because it looks as though it might have been an intriguing game.