Seastalker

There's something down the in the ocean, something terrifying. And you have to face it -- because only you can save the Aquadome, the world's first undersea research station.

The alarm sounds, and your submarine, the Scimitar, is docked nearby. But not so fast -- you haven't even tested the Scimitar in deep water, and the crew in the Aquadome may have a traitor in its ranks. So be careful! You have many possibilities to consider, mysteries to unravel and life-and-death decisions to make!

Success won't come easily. It may not come at all -- because, if you challenge the deep without using all your wits, you just might wind up as shark bait!

Feelies here - https://gallery.guetech.org/seastalker/seastalker.html

Infocom's trademark was abandoned in 2002, but the IP is stilled owned by Activision. This site exists for the preservation of abandonware.