Cthulhu is a single-player modification for Half-Life.
It contains 65 maps, 21 new monsters and 14 new weapons.

Aeons ago, Earth was ruled by The Great Old Ones, beings so alien and terrible that merely seeing them would drive most people mad. Before man's ancestors climbed down from the trees, these being were defeated in a war with The Elder Gods.
But their alien nature meant that they could not be slain in any way that we would understand, so they were imprisoned.
And so they wait, patient and potent until the stars are right and they shall walk forth once again and wipe mankind from the face of the Earth.
You play Ranulf Stafford, an occult investigator in Arkham in the year 1928. Drawn into a nightmare chain of events, you find yourself the only thing standing between mankind and the return of Cthulhu, one of the most dreadful of The Great Old Ones.

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The Miskatonic University library Outside the city of the Great Race of Yith The archaeological dig
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Cthulhu v1.0 Installer

Cthulhu v1.0 Installer

Feb 23, 2006 Full Version 8 comments

This is the installer for Cthulhu: An Unspeakable Mod for Half-Life v1.0

Cthulhu v1.1 Patch

Cthulhu v1.1 Patch

Feb 23, 2006 Patch 4 comments

This is the v1.1 Patch for Cthulhu: An Unspeakable Mod for Half-Life

Post comment Comments  (0 - 10 of 107)
Elitesse May 14 2014, 11:39am says:

Interesting mod, I just hope that it is not too scary!

+1 vote     reply to comment
Guest Feb 22 2014, 12:25am says:

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AdamX777 Oct 11 2013, 7:40pm says:

You should make a Cthulhu mod for Half Life 2 :D

+2 votes     reply to comment
Cryptdidical Nov 15 2013, 7:36am replied:

He is, it's called Cthulhu 2: The Yellow Sign.

+2 votes     reply to comment
Guest Aug 4 2013, 10:09am says:

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asia64 May 4 2013, 7:35am says:

Please help me: How to escape the where have a tomb in a maze cave with 4 valve?(part 9). I have open the tomb with a skull and see a fly monster, i'd kill him and no way to escape this maze cave! The map so dark get my eye so tired/. Sorry for my bad English...

+2 votes     reply to comment
Drponyglock17 Nov 23 2013, 9:18am replied:

open console, type in sv_cheats 50.
quick save and type in restart.
then quick load and type in god and then noclip.
i do it everytime im stuck in a half life mod.

+1 vote     reply to comment
cahal89 Sep 15 2012, 12:45pm buried:


As a fan of H.P. Lovecraft, I figured I'd give this mod a try. By the time I got to the second area with the house, I was quickly infuriated. You, the protagonist, are given NOTHING to defend yourself with and you will suddenly find yourself being chased (and slaughtered) by cultists and zombies. To top it off, there are no forms of health restoration. This mod is a joke and is unplayable, pass it up and play something that wasn't actually designed to just kill the protagonist and enrage the player.

-6 votes     reply to comment
wida Mar 1 2013, 1:58pm replied:

Ignore this guy. He comments on EVERY mod whining how hard it is.

+5 votes     reply to comment
Luktom100 Feb 17 2013, 3:28pm replied:

Ohh stop whining, not every FPS is a Serious Sam type of a game, just think a little bit. Was the original HL about slaughtering enemies wave by wave ?? You must be one of those COD players if you like brainless simplicity, and no challenge in games Mister :P

+5 votes     reply to comment
Xul Feb 1 2013, 7:57am replied:

well, isn't there a bit of survival horror? you can obtain some weapons rather quickly and otherwise run away from them if too many are attacking at once

+1 vote     reply to comment
phipe Jan 3 2013, 6:14am replied:

Cane sword, second floor, pick it up. Kill a cultist and you´ll now have a schmitar too. Another few and soon you got a revolver and a shotgun as well.

If you still haven´t found it i´ll just leave this here.

+2 votes     reply to comment
nietzschesaurus Dec 19 2012, 3:57pm replied:

I got through the game on multiple occasions just find. Maybe you need to brush up on your skills dude. You ever though to just run past the cultist? They stop chasing you after a bit.

+1 vote     reply to comment
fireprowler Nov 16 2012, 4:45am replied:

you missed the sword didn't you... check the walkthrough if it is too hard for you to find it...

+1 vote     reply to comment
claytonian Oct 13 2012, 6:51am replied:


+1 vote     reply to comment
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Release Date
Released Feb 23, 2006
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87 votes submitted.

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Highest Rated (5 agree) 10/10

An incredible mod from start to finish.

Among my favorite half-life mods of all time. :)

Jun 7 2011, 2:20pm by flippedoutkyrii

Lowest Rated (2 agree) 1/10


Apr 1 2013, 7:13am by Urby

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9 years ago
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