Steam maintains a database of game content. New games are frequently leaked through this database, as games need to be added before they can be released. Recently we saw Brutal Legend appear.

Here's a tool to look at the Steam database:

http://cdr.xpaw.ru/

Today, some truly messed up stuff is showing up*:

La-Mulana

The Splatters

Octodad: Dadliest Catch Beta

Duke Nukem 3D: Atomic Edition (Duke Nukem 3D+)

Super House of Dead Ninjas

Fez

LucasArts Test App

Fast and Furious 6

Lococycle

Yogventures!

Hardware

Hardware (Demo)

Dyad

Cut the Rope

Shadow Warrior Complete

Hardware (VIP)

Hardware (Internal)

THE KING OF FIGHTERS XIII

Retro/Grade

Resident Evil: Revelations

THE KING OF FIGHTERS 2002 UNLIMITED MATCH

THE KING OF FIGHTERS '98 ULTIMATE MATCH

Quantum Conundrum 2

Halo 3

Halo 2

Halo: Combat Evolved

The Witness

Angry Birds Space

Angry Birds Seasons

Second Life

Normally, you'd be all like "wtf, this is clearly not real", but...

Take Halo 3

http://cdr.xpaw.ru/app/216800/

The entry links to a Steam Community hub for Halo 3:

http://steamcommunity.com/app/216800/

Duke 3D's entry even has an icon:

As does Shadow Warrior's:

You can see it right there, with your own eyes. This is a Steam URL with Halo 3 displaying in it.

Two possibilities:

1. Valve is adding support for Steam Community hubs for non-Steam games

2. Some or all of this stuff is coming out on Steam. We do know that The Splatters is getting a PC port. We do know that Fez is getting a port to new consoles, and that PC is the most likely console. We have seen a few previously GOG-exclusive titles get Steam releases, so it's possible that Duke 3d and Shadow Warrior might fit that pattern. We do know that Twisted Pixel intended PC versions of Ms. Splosion Man, so Lococycle might not be a stretch. We also know from an MS job posting that they were looking for staffers to evaluate more releases on Steam. We also know that GFWL is basically folded at this point, and that MS has actively worked to make non-GFWL versions of its games available through Steam (see recently the Amazon XBLA PC port pack, all of which activated on Steam).

* Many of the entries predate today, it's just that this particular tool has begun linking the Community Hub data to the database/registry data, and so the information is newly discovered.

http://www.neogaf.com/forum/showpost.php?p=47248418&postcount=1

WHOA??!?!?! o_O;;; no fucking way lol!

I'd love to see the Halo trilogy on Steam.

Quantum Conundrum 2 :D

Releasing Halo 3 on PC after all this time, likely a Win8 exclusive for no real reason would be just like something that Microsoft Game Studios would do.

I wanna know will Xbox fans mad about this since it's over 5 years ago.

Why would we be mad? Games is to be played not ammo for fanboys war.

The port of Halo 3 should better be good!

Not a big deal since It's such a older game. They should throw Reach out there while they are at it.

A lot of people are against timed exclusives, but after 2+ years I hardly see the point to be upset over any timed exclusive. That's plenty of bragging time.

Halo 3 would be cool if they update the game to Halo 4 level, otherwise it's kinda stupid TBH.