Valve has rolled out a significant update to Proton Experimental, the bleeding-edge compatibility layer that allows Windows games to run on Linux and the Steam Deck. Released on September 25, this update addresses several critical compatibility issues that have frustrated players in the community. The patch focuses on restoring functionality for specific titles, including a notable fix for text rendering in Killer7 and resolving launch failures for Crysis and Crysis Wars on newer AMD hardware. Additionally, the update introduces early support for 32-bit OpenXR, signaling Valve's continued expansion of Proton's capabilities beyond standard desktop gaming.
Restoring CEG Protected Games
One of the most urgent issues addressed in this release is the regression affecting games protected by CEG (Copy Enforcement Guard). Following a previous update to Proton Experimental, these titles became unplayable, causing significant disruption for users. The new build successfully reverses this regression, restoring compatibility for affected software. While the changelog does not specify which individual titles were most heavily impacted, this fix is crucial for maintaining the stability of the Proton ecosystem for users relying on protected Windows applications.
Fixing Killer7 Japanese Text Rendering
For fans of the cult classic Killer7, this update brings a much-needed quality-of-life improvement. Previously, Japanese text within the game rendered incorrectly when running through Proton Experimental. This type of text rendering issue can make a game difficult or even impossible to play for users utilizing the Japanese version of the title. By correcting the font and text display errors, Valve ensures that the narrative and interface elements are legible, significantly enhancing the experience for this specific demographic of players.
Resolving AMD CPU Compatibility Issues
The update also targets a specific hardware compatibility problem affecting Crysis and Crysis Wars. These titles could fail to run correctly on certain newer AMD processors that support CPUID faulting. This technical quirk prevented the games from launching or running stably on systems equipped with recent Ryzen hardware. Proton Experimental now includes a dedicated fix for this issue. Although the changelog does not list specific Ryzen generations or CPU models, users who have experienced launch failures or crashes with these games on newer AMD systems should find that the latest Experimental version resolves the problem.
Proton Experimental now includes a fix for that compatibility problem affecting Crysis and Crysis Wars on some newer AMD CPUs.
Additional Game-Specific Corrections
Beyond the headline fixes, the update includes several other targeted corrections. Return to Krondor previously suffered from rendering corruption, a visual glitch that could distort the game's graphics. The new build fixes this issue, ensuring a cleaner visual experience, though specific details regarding the affected graphics hardware were not provided. Additionally, Hide and Moo! received a minor but useful fix for an error that occurred when quitting the game. While small compared to launch failures, these incremental improvements demonstrate the ongoing, granular work Valve performs to refine the compatibility layer.
Early Support for 32-bit OpenXR
The most technical addition in this update is the introduction of early support for 32-bit OpenXR. This feature is particularly relevant for users running older or 32-bit applications that rely on OpenXR for virtual and augmented reality functionality. To utilize this feature on x86 systems, users must set the environment option PROTON_USE_WOW64=1. It is important to note that this support is described as "early," meaning it should be treated as a work in progress rather than a fully stable feature. However, it represents a significant step in expanding Proton's reach into more specialized software categories.
How to Install the Update
For users who already have Proton Experimental installed, the new version should download automatically through Steam. If you have not installed it yet, you can search for "Proton Experimental" in the Steam Store and add it to your Steam Deck or Linux system. As always, Proton Experimental is designed to test newer compatibility fixes and features before they are integrated into the more stable Proton releases. This allows the community to identify and report issues early, helping Valve refine the technology for broader adoption.
Conclusion
This Proton Experimental update is a focused yet impactful release. It addresses critical regressions for CEG-protected games, fixes specific rendering and launch issues for Killer7, Crysis, and Crysis Wars, and introduces foundational support for 32-bit OpenXR. For Linux gamers and Steam Deck users, this patch removes several barriers to playing these specific titles. As Valve continues to iterate on Proton, updates like this one highlight the platform's growing maturity and its commitment to supporting a wide range of Windows games on Linux hardware.