A downloadable game for Windows

Buy Now$4.99 USD or more

Cthon has been Greenlit by the Steam community! Check out Cthon's Steam Greenlight page for additional information, including announcements.

Evil Has Awakened

It is the 24th century, and mankind has only recently begun expanding its reach to the star systems nearest our own Solar System.

A dark and terrible secret is buried within a misshapen moon nestled in the massive asteroid belt of the Epsilon Eridani system. Pythos colony was built there ostensibly to exploit the planetoid's mineral resources, but now they've disturbed a kind of evil that lurks beyond the fringes of our comprehension.

Through an ever-changing labyrinth, you will remold yourself into a cybernetic killing machine using the powerful technologies of a long-dead alien civilization. With these new-found weapons, you will pave a path of aberrant corpses toward the greatest threat to mankind ever encountered.

Cthon is an old school science-fiction first-person shooter, where you become a cybernetic weapon against the dark legions of a powerful evil entity - known only as Cthon - who lurks within the planetoid. It is a classic space horror game, inspired by the likes of Doom, System Shock, and Quake.

The game is 100% Let's Play, stream, and screenshot friendly.


  • Fight - and die - through nine sprawling randomly generated levels. No two games are ever the same, and permanent death ensures unrelenting tension.
  • Modify yourself with the cybernetic technologies of the ancients. A unique upgrade-powering system allows you to get down to the details of character building, and choose the stats you want, when you want, with millions of permutations. Mod types include defensive upgrades like health, armor and speed, offensive upgrades that can increase your damage and rate of fire, and other upgrades that affect the projectiles you fire, like the ability to pierce through multiple targets or shoot bursts of smaller rounds.
  • Slay an extensive array of monstrous creatures, each with intriguing tactical strengths and weaknesses.
  • Choose one of three characters, each of them specialized toward different cybernetic builds.
  • Multiple difficulty levels allow you to adjust the nightmare world to your tastes.
  • Use nano-tech currency to gain a strategic edge - access machines that can forge new items, replenish your resources, and expand your cybernetic framework.
  • The complex, haunting soundtrack complements the dark and oppressive atmosphere.

More information

Published314 days ago
Release date16 days ago
TagsCharacter Customization, First-Person, Monsters, Perma Death, Procedural Generation, Roguelike, Sci-fi, Survival Horror, upgrades
LicenseAll rights reserved
Asset licenseAll rights reserved
Average durationAbout an hour
InputsKeyboard, Mouse
Player countSingleplayer


Buy Now$4.99 USD or more

In order to download this game you must purchase it at or above the minimum price of $4.99 USD. You will get access to the following files:

CTHONv107.zip 240 MB


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Does Gravity Games have an e-mail? There's a few questions I'd like to ask you.

The support email should be accessible if you purchased the game. I would post it here but I want to avoid spam bots.

This game is an absolute ton of fun so far, but... the basic humanoid enemies, I'll call them zombies, attack WAY too fast and deal too much damage. If you get sandwiched between two of them in a hallway, you're basically dead.

In summary, zombies op plz nerf. Still, loving this game!

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Thanks for purchasing/playing! The zombies' attacks were designed to distinguish them from the spiders, who are also melee. Use grenades to soften them up for the killing blow, and also try to accumulate armor; armor applies to each of their claw swipes, so the health you can save increases dramatically with just one or two armor upgrades. Another tactic would be to build a medium-damage shotgun, which can be used to sweep the halls and kill them in usually one hit.

Great job on the game! So much about this one is really nice looking and plays well. I didn't see a place to contact about bugs, but the player rotates on their own with no input sometimes, usually after walking a bit. Oh and I really love the robust upgrades!

Hi, thanks for purchasing/playing! There has been one other report of the player turning on their own sometimes so far; I'm still working on the fix. I believe it only does it with certain kinds of mice, at least as far as I can tell. A workaround may be to try using a different mouse, but be assured that I will continue working on a permanent fix.

Love this game so far. Enjoying it a lot. I have it as a new roguelike series on my YT channel. Looking forward to seeing where this game goes and just what gets added in the future!

love it so far! any thoughts to adding a map? oh, and I think that either the exit didn't spawn in stage 2, or I'm a total idiot. I made a youtube video and literally couldnt find the exit lol. its here if youre interested:

Hey CDPOG! Thanks for purchasing and thanks for playing as always. Couple things: Use Tab to open your automap. As far as the exit, it was there, trust me ;) Usually when you can't find an exit it means there was a turn that you thought was a dead end, but in the many hundreds (thousands?) of times I've playtested there was always a gate to the next level. Also, if you discover the exit gate early only take it if you are confident about surviving the next level. You should almost always strive to scout the whole level and get as many items as you can, or you'll be in for a very uphill battle in the later levels.

ahhhhhhh, there was a map. now i feel dumb. lol.

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I saw your game on Jim Sterling's Greenlight good stuff, and when I saw this, instant buy :)
(I also happen to host a tiny tiny French stream of roguelikes twice a month on twitch. Yours is next in two weeks. I can't promise it will bring you much traffic because my channel is that small, but still. I love your atmosphere. :) )

Hey Morkislair! Thanks so much, I hope you enjoy Cthon. I'd be interested in your stream, even though I can't speak French :) Be sure to tell me where to find it when it goes up!

I love Wolf3D-likes and your visual style - the cover image is fantastic and evokes an Amiga feeling - but I'm not too hot about roguelike and procedural generation, as I think it often leads to impersonal and unbalanced levels. I'll still keep an eye (I also voted for it on Greenlight) and consider buying. If I can leave a suggestion, a later Campaign Mode with fixed, hand-made levels that go beyond the limits of the procedurally generated ones.

Thank you for your interest and for voting on Greenlight! I understand your concerns about the procedural-generated levels. When I set out to develop Cthon my goal was to try to create a shooter experience that felt at least a little different every time you played. Randomness is just as much a part of Cthon's DNA as its obvious references to Wolfenstein 3D, System Shock, Doom and countless others. A fixed-level mode could be interesting, but I unfortunately can't make any guarantees about whether it will ever make it into a release. If you ever reconsider, I do hope you enjoy it immensely.

Maybe it is just my computer, but for some reason my game is running slow, like everything is in slow motion,

My Specs

Operating System:

Windows 10 Home 64-bit


Intel Core i5 4690K @ 3.50GHz

Haswell 22nm Technology


8.00GB Dual-Channel DDR3 @ 801MHz (9-9-9-24)




Generic Non-PnP Monitor (1440x900@60Hz)

NVIDIA GeForce GTX 970 (Gigabyte)

Sorry the game isn't running well for you. Thanks for posting your specs. Just to make sure, have you downloaded the latest version yet? There is a resolution fix in the latest one which resolved a slowness problem someone else had.

Thank you so much for the quick response. I got the patch late, but it seems to have fixed the problem, I finally got down to playing it and let me just say you made me a big fan of your game. Keep up the great work and Thanks again.

Deleted post


I bought the game yesterday and I have the same problem. Though it starts out fine, it eventually, after a couple of levels, turn slow. So how do you download the latest version?

Hmm. If you bought it yesterday it should be the latest version already. That's weird that it starts okay and then gets slow. Can you tell me your system specs?

I don't know too much of what goes on behind the screen, but here goes:

xin 10 home, 64bit

intel core i5-3230m, 2.6ghz

8gb ram

nvidia Geforcre GT750M, 6087 mb

1920x1080 60hz

its a lenovo laptop

Yeah it is weird, it seems like it happens pretty sudden the shift to slow...

thanks for the answer and the promising game:)

Those specs should be more than enough to run it. I'll see if I can replicate the problem and find a fix for it.

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Hey there,

One of the things you may want to try is a malware scan if you haven't done so already. That might be messing with your memory usage. You can also email a system dump (Run msinfo32 and then File -> Export) to the support email and I can look through it.

I ran a scan and nothing showed up. I'll email you the system info.

Just to mention it, I haven't experienced the problem since, but I'm still none the wiser. I did get to the last levels though, it really kicks off!

Saw this on Greenlight, saw that we got Steam keys if we bought it here first, came and threw money at the screen. Have "completed" (read: died on) a few runs now, and think it's off to a really solid start. A few quality of life requests:

  • Adjustable mouse sensitivity
  • Ability to exit out of all menus with a single key (e.g. Esc) instead of reaching over to tap "i" again
  • Rebindable keys (less of a concern, admittedly - but again, reaching over to hit "i" is less than convenient)
  • Text is a little hard to read (though this may be caused by the resolution, which I know you folks are already working on)
Those aside, I'm REALLY enjoying the game so far, and look forward to seeing how it develops!

Is there a way to alt-tab out of this game or play it windowed?

Let me upload a new version with a fullscreen toggle key. I'm still working on an actual in-game interface for graphics options but this will hopefully work okay in the mean time. F4 will allow you to toggle it between windowed and fullscreen. You'll also be able to resize the window from the default 640x480 size. You can still switch between windows if you pause the game.

Unfortunately, alt-tab and alt-ctrl-del seem to freeze the game and force you to close it with the task manager; I'm still researching the problem and will hopefully find a fix for that soon.

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Is there a way to change resolution options somehow? The fact that it's forcing 640x480 is really messing things up, and by that I mean it's running at like 25% of the intended speed and messes up everything else in the background.

Currently there are no resolution controls, but adding them is a major goal for us in the next versions. I'm sorry the game isn't working very well for you, would you be willing to share your system specs with the support email?


A new version has been uploaded, which eliminates the forced resolution. Please download it and let me know how it goes. I hope it runs better for you.

I have already said this on Steam, but the game is running fine now that it doesn't force everything into 640x480. If you want, I can help you test the build if things like resolution options are added in to see how it goes, because I doubt this would be a problem to my system exclusively. Would be a shame to launch on steam with an issue like that in place.

(Edited 1 time)

No doubt! I highly doubt it is only your system; I have a feeling newer operating systems really dislike the tiny resolution. I bet if it forced it to something like 1920x1080 (for example) it would have done just fine. A little bit of the contrast is lost when its not in a forced resolution, so I will do some research on adjusting gamma so you can make the game darker if needed. I'm making a list of all the options we'll need and I hope to have them ready as one big update for the Steam release.

(Edited 2 times)

Yeah, resolutions smaller than 800x640 or something like that are not common anymore these days, heck, I think Windows 8.1 won't even let me select 640x480 anymore. Might be where these issues are comming from.

Actually, I just checked what Windows 8.1 lets me choose - The lowest is 1024x768

Ah! That's got to be it. No operating system could possible want a piece of software to force a resolution that it doesn't even know about! Thank you so much for helping me troubleshoot that; it was a bit of a struggle but I think it will make everyone's experience go a lot smoother from here out. I haven't used Windows 8.1 much myself, let alone checked its supported resolutions.

Glad I could help. If you ever need something tested on windows 8.1, just hit me up, I'll glady run it on my rig to see if everything works right.

Hey Gravity Games! CTHON has a really interesting premise, and I am loving the art style. I know you are currently running a Greenlight campaign and are looking to release on Steam, but have you also looked into a GOG release? I think this game would do well on that platform.

Thank you for your interest in Cthon! I am considering doing a GOG release, but it will most likely coincide with the Steam release, when all the essential improvements that need to be made are in the game.

Sounds great! Can't wait to try it out. Cheers.

Bought, and really enjoyed the game, but only a few things;

Can we get an options menu in the main menu?

I found that sound settings were only for that specific "life" if you will. It would be nice for some resolution controls too, at least a windowed mode.

Classic FPS Controls/Keybindings?

It would be really nice to be able to use traditional FPS controls (Arrow Keys + Ctrl) so being able to set keybindings would be nice too.

Overall it's a great game for $5 but I think that it needs a little more tweaking before it hits Steam.

Thank you for purchasing! I agree with your assessment; the game will definitely require tweaking before the Steam launch. There are likely a couple bugs still floating around and the general interface needs improvement. Rest assured this will be fixed before the Steam release.


I'm going to go sink some more time into this now!

If we do run into any issues (bugs) or have any suggestions, where is it best to reach you?

A support email should have displayed when the game was purchased; that's probably the best place to report any issues. I would post it here but I want to discourage spam. Let me know if you can't find and I can try to message it to you privately (assuming itch supports that kind of thing).

Hi Gravity Games! I just played CTHON, and I really liked it - enough that I would like to put up a one-shot video of it on my YouTube channel, here. The video is only about twenty minutes long and features me exploring the first level of the game, dying a couple of times, and poking around a bit with the item system.

Do you have any objection to this video going up? Additionally, would you mind my using your cover photo - the one of the zombie in a pressure suit - as my thumbnail?

(Edited 1 time)

Hi General Confusion, I would be positively honored for you to post it! The game is absolutely Let's Play/video/screenshot friendly; you may of course use the game cover (the pressure suit zombie) in your materials, or any other graphics you would find fitting. Thank you very much for asking!

I should have done this before but I will clarify in the description that the game is exhibition friendly. I'm eager to see it!!

Thanks very much! I'll send you a link to the video when it goes up on Saturday (I pre-record my videos for ease of scheduling), and if you would like to share it around to people or use it in promotional material, please feel free; just let people know who recorded it!

(Edited 1 time)

Hello again! Here's that link to the video that I promised.

As I said before, I enjoyed the game a great deal! There are still a few rough spots - the entire lack of a save function (at least I didn't find one) is something that threw me a bit, since it means you have to do the whole game in one sitting if you want to play through it all - but overall I think you've done very well so far, and I'm looking forward to seeing the game expand. Thanks for your work!

(Edited 1 time)

Hey there!

Thanks for the video.

One thing you should know - the gameplay in the video looked a little sluggish compared to what is intended; I have a feeling your machine is one of the ones that dislikes resolution changes, which is patched in the current version. Try it out and it should run significantly faster for you.

EDIT: Also, you may consider trying again on Standard mode, that's what is intended for pretty much everyone until you gain the experience to play on Hardcore. Hardcore is borderline masochistic ;)

Save functionality is another thing that is in the list of planned features.

Nice atmosphere and cool art.
So far I've got to the second world. Really like the upgrade/inventory/energy system. Forces you to be selective with what you carry.

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Thank you for purchasing! I'm glad you are enjoying it so far. Updates will be ongoing so be sure to check back here often for the latest version.