Just tried it (on another XP system without steam installed). Leaving the steam_api.dll alone, you get a "Fatal Error - steam must be running" or something like that. Deleting it, you get the exact same result I mentioned above. A couple of errors popping and a black screen after the main menu.

I discovered that Abyss: The Wraiths of Eden can be converted to DRM-Free by adding a 'steam_appid.txt' file in the game directory and writing the number '284710' in it. It's the same solution as Nightmares from the Deep, so I guess all games from Artifex Mundi work like this. If anyone has more games from them, I'd would be nice if you check adding the file with its app_id on it and check if that works.

Added Cognition Erica Reed stuff, ep 1 and 2. I'll hazard a guess that the other eps also work drm-free. Game works whether you delete the steam_api/nativeworks.dll or not.

edit: is it just me or does the drm-free version not save?

There are a few games that use the Steam Cloud feature to save. So without Steam you cannot save or load (without much tweaking). I think pedrovay2003 mentioned that a few times here, I sadly do not know much about that topic.

Surely that isn't ever mandatory? I have the entire Steam Cloud shut off in the options menu and have never had a problem.

I'm not sure how it works, but I've run into the same issue with Super House of Dead Ninjas. No saves when playing without steam.

That should not be an issue at all, as all the cloud save do is back up the local save location folder (or file) of the game to the cloud.

Takedown: Red Sabre is also messed up if you're offline or off Steam.

Shannon Tweed's Attack Of The Groupies. Tested on Windows XP.
Really.

Thanks for taking one for the team. We'll hold a memorial service for your lost time.

Very interesting article by Ethan Lee(Programmer and Linux porter) on DRM: https://plus.google.com/102593483001615978126/posts/9CnJH98W9pK

Anybody have Summoner on Steam?

If so - does it force Steam to boot if you have Steam closed and boot the EXE file from its game-folder?

EDIT:
So, someone told me it doesn't have CEG.
So, I bought it from GameFly on sale ($1.25) - and then w/ 15% off (JUN15OFF), that knocked it down to $1.06.
Just tried launching the game from Steam - yep, no Steam CEG tied to it. :D
DRM-FREE on Steam.

Added Gray Matter, will add Summoner time permitting (unless someone else does).

Are you kidding me? I didn't know anything about this till I entered this post!!! how could it be?? I have some of that games so I could install them on Linux without Steam!!

Thank you sooo much! I'm going to try how they work. Really thank you ;)

EDIT: Wanna say install Win games on Linux (Like Fallout 3 or Fable). I had to virtualise Steam in playonlinux to play that games there