Uncovering Every Valve Game Revealed in the Massive Steam Leak

On August 29, a massive leak of approximately 13 terabytes of Steam depot data hit the internet, potentially marking one of the largest leaks in gaming history. This treasure trove includes prototype builds for a staggering number of games, featuring several first-party titles from Valve, such as Portal 2, Counter-Strike: Global Offensive, and Left 4 Dead 2.

The full extent of the “Steam2” leak is still being unraveled, as enthusiasts are busy cataloging its vast contents. What is clear is that the depot files span from 2003 to 2013, and the nearly 13-terabyte torrent includes builds from both third-party developers and Valve’s own lineup.

Details on third-party games remain sparse, likely because many are focused on the wealth of information found in Valve’s prototypes. Here’s what we know so far, with the understanding that this story will evolve in the coming weeks.

First off, let’s address the elephant in the room: no playable builds of Half-Life 3 or Half-Life 2: Episode 3 have surfaced in this leak. However, there is still some Half-Life content to discuss.

The standout find is a model for the “weaponizer” gun from Half-Life 2: Episode 3. Back in 2011, filenames related to this game leaked, including references to an “icegun,” a “flamethrower,” and multiple instances of a “weaponizer.” While this discovery didn’t make waves at the time, it gained traction after Valve released the Half-Life 2: 20th Anniversary Documentary in 2024, which included clips of weapons intended for Episode 3, such as the Ice Gun and a brief glimpse of what fans believe to be the Weaponizer. This model appears in the Portal 2 prototype build, although it seems to serve as a placeholder for a scrapped Paint Gun. There are also unconfirmed reports of filenames in an “ep3” depot, but those should be taken with caution for now.

Speaking of Portal 2, the leak has revealed at least two prototype builds of Valve’s 2011 game, which are the most exciting finds so far. The 2009 version of the Portal 2 prototype is quite rough, but for fans of early game concepts, it offers a glimpse into unfinished cutscenes and placeholder models. For example, an early version of the game’s intro sequence from the 2009 build has been shared.

The 2010 build is where things get really intriguing. It contains working, albeit incomplete, versions of three scrapped Portal 2 mechanics: Adhesive Gel, the Paint Gun, and a slow-motion bullet-time mechanic.

Interestingly, both the Adhesive Gel and the Paint Gun were known to fans since the game’s release, as developers discussed them in the commentary mode. However, this is the first time they’ve been seen in action, and while it’s clear why the developers chose to cut them, using Adhesive Gel to walk on walls looks incredibly cool.

The slow-motion mechanic also appears to be fully realized before being scrapped, complete with slowed-down sound effects when activated.

There’s a wealth of Counter-Strike: Global Offensive content emerging, with at least three distinct prototype builds identified, though they all seem quite similar. These builds feature PS3 and Xbox 360 icons, suggesting they were work-in-progress ports. One build includes scrapped models, including one of a female character, and showcases a clean version of the HUD along with several cut weapon animations. One particularly amusing aspect is a build that features “family guy ragdoll physics,” which is too entertaining not to mention.

Counter-Strike fans will likely be most intrigued by the scrapped maps found in one of the later builds, which appear to be inspired by maps from the original Left 4 Dead. These maps don’t seem to be direct copies but rather recreations, raising questions about why they were ultimately discarded.

As for Left 4 Dead 2, there seem to be at least two prototype builds, though they are reportedly quite buggy and crash at certain points. While the discoveries here aren’t as thrilling as those from other titles, there are still some interesting tidbits. For instance, players can jump significantly higher in these builds, and the placeholder audio in the Dark Carnival level’s concert section is hilariously loud.

Interestingly, many of Left 4 Dead’s maps are included in the Left 4 Dead 2 builds, allowing players to experience them with the survivors from the sequel, likely for testing purposes.

For those who aren’t deeply familiar with Valve’s history, F-Stop might not ring a bell. However, for dedicated fans, it’s a name that sparks excitement. F-Stop was a canceled prequel to Portal, conceived during a brief experimental phase in 2007 known as “the Directed Design Experiments.” The team explored various concepts, one of which was F-Stop, where gameplay revolved around taking pictures and manipulating them to solve puzzles, reminiscent of the game Superliminal. Although the project was ultimately scrapped, some assets have been found in one of the Portal 2 prototypes.

While a prototype of F-Stop isn’t included in the leak, a nearly 10-minute-long placeholder dialogue featuring Cave Johnson has surfaced, originally intended for F-Stop. In this dialogue, he humorously instructs players to pick up “the Aperture Science Spirit Camera” and take pictures of his “big old butt.” It’s a bittersweet reminder of what could have been had the project moved forward.