Yes, every Ubisoft game I've seen on there needs uPlay, so won't make the list. The basic requirements I'm aiming for are "Once you have the files you'll never need to use any client for them again, even if you reinstall Windows / buy a new computer". Thanks for the entries! uPlay titles aside, I could find no way of getting The Talos Principle to work offline. It would throw up unusual in-game Login and Password boxes seemingly hard-coded into the game or it wouldn't even reach the main menu (from what I remember it just got stuck cycling between asking for a login vs showing the initial pre-main menu startup screen). Trying to bypass it with /c=.. -AUTH_LOGIN=unused command line switch didn't work, nor did copying the command line variables that the Epic Launcher creates (without the client running). If anyone knows of a way to do so please post as Talos Principle is a very highly rated title. And yeah I suspect devs have to ask for DRM to be added / override it rather than it be default (something Steam should have been from the start too).

I do own This War of Mine here on GOG, but it's one of those games where I personally didn't like the latest "story" builds much and stuck with the older version as the new ones seemed more buggy, so for that one I did rely on PCGamingWiki. I would presume any DRM that was added in a patch was done accidentally by 11-bit Studios as it doesn't make sense to intentionally shove DRM into it whilst selling a GOG version DRM-Free. Thanks for the correction though.

Thanks for the list. I did try playing e.g. Batman Arkham Asylum by downloading/installing the game on one PC, 7zipping the whole installation directory, copying the game to another PC and playing it there. Seemed to work fine, at least the little I played. It is nice that those Batman games appeared DRM-free, and Epic even gave them away for free. :)

A comment to the test methology: Using that test methology, is it certain that the game will always run directly from the installed files, even on a different PC? I know many don't have the possibility to copy the installed game to another PC (which has no Epic client) and then test it there, but do you see any possibility some game was like that, ie. it passes your test, yet fails to run on another similar offline PC without the Epic client? Let's assume of course that both PCs have other external dependencies in place, like the DirectX, PhysX etc. versions the game requires. (The game failing on the other PC due to missing PhysX or whatever is not DRM of course, as long as that dependency can be installed separately.)

The real "litmus test" is indeed downloading on one PC and testing on another (ideally with very different hardware). I do this where possible in our house (eg, download on a laptop with Intel iGPU and test on a desktop with an nVidia GPU), to rule out any potential Epic equivalent of Steam's CEG (which works by downloading the whole game minus the .exe, then from a completely different server it uploads your unique motherboard hardware ID (same thing Windows OEM "Digital Licenses" are locked to), which then creates and downloads a custom unique .exe that's locked to the motherboard of whichever PC was used to initially download the game via the client for the first time). That's Steam's CEG. So far I haven't seen any evidence of any Epic Store equivalent (it's either a basic client check or use 3rd party Denuvo / uPlay, etc), and so far Epic games that don't need a client will generally work on another PC without restriction (or if they do need a client, they will usually fail even on the same PC).

At the moment though, I do appreciate that most people only have one PC to test with and am happy to simply ask that they test that the client isn't being silently "called" in the background (by renaming the client's .exe / folder before testing). If that situation ever changes and if an "Epic CEG" comes into existence, I can simply go back update whatever entries are required in future (and it's a lot easier doing this in spreadsheet format than to hunt down individual forum posts)! Thanks.

Does that mean The Foundation DLC is DRM Free?

As of now a few more that are currently DRM free are: A Knights Quest, Kine, Manifold Garden, Supermash and for now Griftlands is too. Griftlands is by Klei so they may add drm once out of the alpha stage. They don't have a great reputation as far as I can tell considering they pulled the Mark of the ninja special edition upgrade on GOG to push people to buy the remastered version on Steam, which is the only way to play the dlc at the present.

Last years Subnautica works without it but it runs at max CPU power for no good reason. even when the game's paused.
I'm not sure if that's caused by the crap Unity game engine or something else.

Having a backup list stored somewhere other than google would be a good idea too.

Regarding 3rd party dependency packages my experience with the temporarily free titles has been that the game either either doesn't need any installed, or has them stored in the install directory to manually install if need be. The only time I needed a 3rd party download is when the package in the folder didn't suit Windows 10 (one of the Arkham games) and needed to download the .NET / C++ package from Microsoft directly to work - Windows 10 organised it all rather seamlessly. So in other words simply archiving the installation at the moment and porting it elsewhere is very possible as long as it isn't directly dependent on the client.

The testing strategy of renaming the launcher etc is an approach that some have used on PCGW, but I didn't trust that method either. My testing has been myself and others following the "gold standard" of copying it to a completely different client-free PC setup. Even my personal testing went as far as running the games 100% offline. For the most part, PCGW has been accurate, but the titles aren't reliably kept up to date with version changes on Epic.

@AB2012
As for The Talos Principle, nope I tried all the same techniques as you did. The game "launches" but won't let you go any further than the first load screen without the client authenticating the game. For this particular title? It's not surprising it got DRM-locked: Croteam has got a phobia for pirates.

Ancestors the human odyssey I can play without the Epic client.

Hm? Ghostbusters Remastered worked for me without using any additional parameters...

The patch they pushed out with the DLC could have added back in the client check I guess, but since they made a point of not requiring the client before I kind of doubt it. I could check though, sometime soon. I want to take another look at DLSS 2.0 anyway.

Thanks. I added them though made a note about Griftlands Alpha state.

Yes I have an offline backup. In fact I've also set it so that anyone can download an offline copy (ODS / XLSX / PDF / HTML) or print without needing to login.

Weird. It didn't work for me without -EpicPortal but it does now. Even better.

Since I have a dedicated partition for the games and 2 Operating Systems on the same drive, it's very easy to test for DRM free games. However all the games I tested are included on the list already.

I want to add that Celeste is portable, meaning you can place the game on a USB pen drive and play anyware.

Nice to see a new list forming. Hard to argue against free and DRM-free on the side. I tested today's Sherlock Holmes: Crimes and Punishment on Win10, no need of client.

On a side note, I feel like another ignored client is Twitch. Pretty much every single Twitch Prime game I've gotten and checked is DRM-free so far.