In the 1980s, you're a fortune seeker (and trained diver) on a small island probably located in the Northern Caribbean. A friend consigns you to a map that bears coordinates of a wreck previously unknown - and gets assassinated moments after he parts ways with you. You have to team up with some locals in order to get a chance to seek for the wreck, but the locals are fortune seekers just as you, and cannot be trusted. Will you get out of this situation alive?
The cons of this game cannot be denied. The pros neither: Besides the pretty unspoiled setting (for 1984, that is), Cutthroats starts like a predecessor of an open world game. NPCs roam about freely, minding their own business, or (less pleasant) yours. The game gives you the feeling of exploring a game world that advances on its own. That, in combination with the realistic Caribbean setting and the fascinating (though stereotype) NPCs, provides for a mindblasting experience.
But then, the cons. Since time trickles away relentlessly, and since time triggers (and disables) events, there's a multitude of situations where being at the wrong place at the wrong time (or rather not being at the right place at the right time) renders the game unwinnable. Sometimes even without telling you so. Sometimes your only fault is to carry the wrong things with you at a certain time and place, or to give a wrong answer to an NPC. This way you'll do a LOT of try & error, which is only acceptable if you're aware of what's happening, which in many cases you aren't. Also, the second part of the game (the actual treasure hunt) is a bit dull.
In summary: Great premises, but full of doubtful design decisions. If you can find the original game package on Ebay, you'll be rewarded with hilarious feelies, as ever so often with Infocom games.