I did indeed test all five games on a PC that didn't have Steam installed or found anywhere in the registry, and they all ran perfectly fine. :D

If true, me too. This I have to try out sometime, if I can arrange a good testing setup (a modern computer with no Steam whatsoever). Heck, I would have thought these would have been the first games the people contributing to this thread would have tested?

I wonder if this applies also to other "Valve" games like Portal and Portal 2? I recall googling for DRM-removal instructions for either of the Portal games before, and they were quite complicated, with all kinds of "Steam emulators" and stuff, so I decided to leave it be. How ironic if the "crack" would have been simply to run the games directly from the .exe's.

Half-Life 2 should run fine (though I don't have a steam-clean setup), but Portal 2 doesn't run. It starts without launching steam but after loading the main menu ther are the two entries "No Steam found" and "Exit" instead of the usual "Start Game", "Load Game", etc. I doubt it will work on a clean setup. Portal 1 runs fine under Linux but I haven't tested it on Windows lately.
@ Half-Life 2: A month ago it required CEG so I'm surprised as well it works fine just now. And I can't think of an update through steam that made it DRM-free (or I'm just senile...).

Well then, let's hope HL2 stays this way, and this isn't just some unintentional hiccup that Valve will "correct" soon... :)

I guess this just underscores one point that has been said in this thread before: in order for this DRM-free list to stay meaningful, people would have to retest over and over again the games listed here (or the games which are thought to have DRM), because things may change either way over time...

So if someone e.g. buys a Steam game based on this list thinking it is DRM-free, and it is not, what then? Who's responsible and gives a refund? Bazilizek? :)

That's a difficult matter.

If the list isn't actual or trustworthy, it's useless, because you bother with DRM before buying a game. If you already own that game, the list is only a suggestion what game possibly runs DRM-free. But isn't this the major flaw of all wikis? Every information could be corrupted. On the other hand many people can help make the list better (or worse...).
Since this is not official, it will never be in a status of trustworthy where you can take all informations at face vault.
It should be clear that you can't trust a wiki to 100% but we could add a disclaimer to the list to be sure ;)

A little utopia and my boring thoughts: An option to make this all better and more reliable would be 1) creating some sort of mods which should be reliable and test a lot of games and 2) make a discussion for every game and gather a lot of feedback - even the game has been proved to be DRM-free a long time ago. 3) Additional you could use a (anonymous) voting system to check if a game works or not. In this way you could provide a stochastic probability (if the feedback is large enough). But that requires so much community work as long VALVe or some publishers/developers on steam don't make an own official list.

I just tried the Windows version of Portal, and it, too, is DRM-free. I'll have access to a computer that has never had Steam installed on it in about an hour or so, so I'll test all these games on there and post an update. I also remember the Half-Life 2 and everything that runs through it being CEG locked, so this is quite a surprise. (I hadn't had these games installed for a long time, and only decided to try them again after I learned the Linux version of Half-Life 2 was DRM-free, so I have no idea when an update may have happened.)

Okay, so, I just tried the Half-Life games that run in the Source engine and the first Portal game on a Windows 8 machine that has never, EVER had Steam installed on it, and all of them ran absolutely perfectly. I can now confirm with absolute certainty that, at least for now, Portal, Half-Life: Source, Half-Life 2, Episode One, Episode 2, and Lost Coast are all completely DRM-free.

I also tested the Linux versions of these same games after doing a complete reinstallation of Linux Mint 15, and they all ran beautifully as well. I can't even express how happy this makes me, as these are some of my favorite games of all time.

Honestly, I think this is a mistake on Valve's part, so if you have the games, I suggest backing them up while you can. If this ISN'T a mistake, then Valve should really be advertising that they're removing DRM in their games; They'd get a ton of anti-DRM players (like I am) to grab a bunch of their games.

EDIT: It's also worth mentioning that I didn't even do an initial startup of the games as soon as they were done downloading from Steam -- I literally just downloaded them, quit Steam, and backed the folders up.

Excellent! Thanks for the good news. I shall sacrifice a goat to the Gaben!

I'm not so sure, there have been reports since Steam appeared on Linux that Valve's games were DRM-free there. I admit I doubted that would spread to Windows (not that I heard any rumours that it would), but now that it has, I'd bet on it being deliberate (because it's much more efficient keeping the codebase as similar as possible between the platforms).

The fact that they don't advertise it is, I believe, rather a sign that the anti-DRM people are too few to really matter to them. They don't advertise any other DRM-free game on their service as such either.

Valve aren't stupid, and if they figure it's not cost-effective keeping DRM in their games for three platforms (or keeping it for one or two, while keeping it up to date so it doesn't break stuff when the games get updated otherwise), they'll cut it out. At the same time, they'll do it for time and cost reasons, not to gain goodwill from a very small group of gamers.

1 - Valve have often stated how they are for openness and open systems, so it most most likely by design

2 - DRM Free is only a sales gimmick that only goes so far, and quite a lot of people just don't care that much, so it depends how important it is to advertise for them or not as long as it is not part of some grander schemes of things

3 - No point doing so, as the DRM free fanatics will just say that Steam in itself is drm, and that you can not get DRM free games from them, so even with advertising this fact it will not get those people here.

Vast majority is the term I would use.

I can see where you're coming from with 2 and 3, but I disagree with 1. Valve can talk about their openness until they're blue in the face, but they STANDARDIZED the most popular way of locking games down. Hell, even most Steam games for Linux, an open-source OS, are locked to Steam. That's about as closed as you can get. Not only that, but their other games, like Portal 2, Left 4 Dead, and Left 4 Dead 2 still require Steam to be running. I'd love to see these games also get freed in the future, but I'm not holding my breath for a solution any time soon. Mac is, oddly, the only platform Steam is on that almost guarantees no DRM, since I believe the CEG component is completely absent from the Mac version (although some are still locked down).

As far as people not caring about DRM-free stuff, I think that'll be changing very soon, thanks to Kickstarter. Almost every game on there is advertised as being DRM-free, and people are going to take notice. I've also noticed people specifically asking on Kickstarter if games will be DRM-free.

Steam needed some kind of authorization solution for publishers to accept it. I'm not saying Gaben hates DRM or anything, but it was likely a decision completely out of their hands if they foresaw anything close to what Steam has become.

And open platform has little to do with DRM. Windows is the most popular open platform in the world and requires authorization to install and use. Open platform just means anyone can make, release, sell and run any program on the system. Gaben has said he wants Steam to be open someday, and Greenlight is step one in the transition.

So why not Portal 2 then?

"Openness and open systems" have really nothing to do with DRM-free. It is also funny how you keep complaining about DRM-free being just a marketing gimmick, while you have completely bought the Valve marketing of "favoring openness and open systems", when at the same time Valve is working on Steambox.

At least if you include also the Steam users who are barely tolerating it, which is not the same as being fine with it and not caring. Like me, for instance,or all the people who were complaining about the non-working offline mode on Steam forums this summer.

Have you tried Portal 2?

Would be funny if it was now :)