Thirty Fathoms
A free online text adventure in five acts. 1962. Two hundred and forty feet of Atlantic, and a hose that only reaches so far.
The hospital ship Cordelia went down in 1943 in forty fathoms, and for nineteen years nobody has looked for her — which, given how precisely three separate governments know where she is, has always struck you as a lot of not looking.
Now a man in a good coat has chartered a barge, hired a hard-hat diver at four times the rate, and asked for exactly one thing off her: a strongroom consignment listed on no manifest anywhere, called Cargo 9. You are Alec Rae. Eleven hundred hours in a copper helmet and no illusions about any of it.
The mechanic is the sea
Going down is free. Coming up is not. Nitrogen dissolves into you at depth and comes out again only if you hang at the thirty-foot stage on the way home — and your air has to cover the descent, the work, the ascent and the hanging. Men forget the hanging. There is a dive table on the barge that tells you the arithmetic before you get wet, and it is the same arithmetic the game uses.
Then there is the umbilical: air, lifeline and telephone laid up in one hose that will not turn corners. Go in and come out the same way or it loops round a stanchion and stops you dead. Some rooms it will not follow you into at all, and getting into those means unclipping — which doubles your air consumption, puts out your helmet lamp, and takes away Ruth Kelsall on the telephone, who is the only person in this game who ever warns you about anything.
Five dives
Act I — The Barge. Surface. Nothing can kill you. Learn the suit, the table and the telephone, and find the fault in the compressor by putting your hand behind it, because Ruth will not sign you down until somebody tells her why it is running hot.
Act II — The Boat Deck. Sixty feet. A davit that will not be levered off a door and must be floated instead, a conger in an unlit vent trunk, and a ward with two hundred and fourteen made beds in it that were never slept in.
Act III — The Engine Spaces. An air pocket you can put your helmet into and stop breathing your own supply, and three feet of coal ash that will blind the entire deck for ten minutes if you put a boot in it.
Act IV — No. 4 Hold. A cutting torch that draws its oxygen off the same bank you are breathing, so every cut is a bite out of your own way home. And one piece of entirely optional work here that is worth more than everything else on the ship.
Act V — Below the Keel. Two hundred and fifty-five feet, past the table, where narcosis takes about one minute in three and you do not notice losing them.
Three endings, and which one you get turns on a decision you made two acts earlier without knowing it was a decision.
Roughly an hour and a half to two hours. It is a shorter game than Ashkar and a denser one: there is less to look at and more to decide, because every single turn spends air you will want back on the way up. Autosaves every turn, checkpoints at every act.
Stuck?
The hint page gives you one nudge at a time, act by act, without spoiling anything you have not asked about. The full walkthrough is there if you would rather just be told.