Did you let it update through Steam, or did you install a retail patch over the Steam installation?

EDIT: I just downloaded it through Steam, and I can't get it going without the client. It keeps giving me an error about not being able to find Steam, and then it automatically launches my web browser and brings me to the Steam homepage.

It was a manual update (with official German patch files) not a steam update. I will try to test it this weekend. Maybe I can then post a ling to the patch files.

I just tried Deus Ex (GOTY) again and unfortunately I have to say that it does not work (installed both New Vision HD pack AND German patch). Maybe it woked because I still had Windows XP when I last tested it.

Edit: And forget all this again. I knew that I managed to get this game working through patching but it was the patch to the newest multiplayer version which you can get here:

http://www.moddb.com/games/deus-ex/downloads/patch-to-v1112fm

After patching there is no steam required anymore.

Thanks to AMRIT9037 i not only was now able to play Freedom Planet I can also confirm that it runs without Steam :)

Win7/64 here :)

It`s possible to play Wings of Vi without steam running (which is even confirmed by the developer on his ask.fm page)
I was also able to play the early access games Gang Beasts and Rivals of Aether without steam, but since they are early alpha builds, it could be patched in later versions
My OS is Windos 8.1

Awesome, thanks for the info; I've updated the wiki with Wings of Vi. As for the others, let's see what happens when they leave Early Access for now, since you're absolutely right about the potential for updates to change their DRM-free statuses in the future.

Has anyone happened to pick up Soma on Steam? I ask because apparently, there's actually a DRM-free, non-Steam version included with the Steam copy, which can be found in the installation folder.

I've added The Deer God, tested on Windows 10.

Also, when editing the wiki, is there an easier way to center the checkmarks / questionmarks in the cells without having to edit source?

Okay confirmed: SOMA and Keep Talking and Nobody Explodes are both DRM-free, at least in Windows; I'll test SOMA in Linux later.

I actually can't even edit the page in anything other than Internet Explorer anymore; it just does nothing. In Internet Explorer, it goes directly to the source, though, so it always centers when I do it. I fixed The Deer God for you, but I have no advice beyond that. :/

Thanks for that -- it's unfortunate but the backend coding for Wikia seems to be quite poorly done. I seem to encounter a lot of load issues as well as problems editing articles. It's a shame its not to the same standards as Wikipedia, despite being for-profit.

Maybe I'll try switching to IE to add new entries, since trying to do so with Chrome has been pretty inconsistent with respect to access editing source.

The newly released Planetbase can be added to the list of games that can be run without the client. Tested on Windows 7.

Does anyone know if the Windows version of Wasteland 2 (the Linux version is already on the list) can be run without the client as well? I'm asking this because quite a lot of Unity engine games like Interstellaria, Pillars of Eternity and Windward come without any extra protection so it might be safe to assume that this is the case for most Unity engine games as long as they don't have a multiplayer mode (like 7 Days to Die and Rust) that is dependent on Steamworks and therefore need the client to run.

The great Broforce is now finally out of early access state and I can confirm that you can run it without Steam Client active. (Win7/64)

Hammerwatch for Linux doesn't require Steam, tested on 2 different systems without Steam installed.