You might recall Epic had announced EAC support for games runs through Proton back in September. A game developer needed to supposedly upgrade to the latest SDK and enable a few checkboxes before export:

Starting with the latest SDK release, developers can activate anti-cheat support for Linux via Wine or Proton with just a few clicks in the Epic Online Services Developer Portal.

Some developers have shed some light as to whether supporting EAC through Proton is actually easy. One of the developers of Warhammer: Vermintide 2 was looking into supporting the game through Proton, and he is quoted from the Steam forums as saying:

It’s far more complex than first suspected – EAC has two versions. Non-EOS and EOS (Epic Online Services). Most games historically use Non-EOS EAC. It’s the one Vermintide 2 uses as well. Epic only added Proton support for the EOS version of EAC. Therefore in order to implement Proton support for Vermintide 2, a huge amount of reworking of the EAC implementation would be required, which may also require all players to authenticate with Epic Online Services as well – perhaps even logging in to the Epic environment (to be confirmed, however).

So the “just a few clicks” statement made in the original announcement wasn’t entirely accurate, and would only apply to titles using the EOS version of EAC, which simply hasn’t been many games aside from either pretty new ones, and likely predominantly Epic exclusive titles.

We are still looking at what is or isn’t going to be possible, but it’s not as easy as it was made out to be – far from it in fact.

There may be other solutions or workarounds, but ripping out the old EAC and rewriting everything to implement “NuEAC” and potentially asking our entire playerbase to connect through and sign through EOS for an honestly tiny market share that was (and would remain) unsupported from the get go might be a deal breaker.

Going from this explaination, this is the probable reason why there’s been so few titles with EAC to work through Proton so far. But yesterday, Valve wrote a new post regarding EAC. The post said that the company has been working with Epic to make supporting EAC titles on the Steam Deck or through Proton even easier. Game binaries no longer have to be updated, neither does the developer need to opt-in to the latest SDK or use Epic Online Services. If we go to the Steamworks Documentation, enabling EAC support is a three-step process:

1. Go into the EAC settings on the EAC partner site and enable Linux support from the dashboard.
2. Once that’s done, download the EAC Linux library (easyanticheat_x64.so) for the SDK version integrated with your game, and add it to your depot next to the Windows library (EasyAntiCheat_x64.dll).
3. Lastly, on the Steamworks site, publish a new build of your game containing the new depot contents. (You don’t have to make any changes to the game executable, just include the new files in the depot contents.)

Seems like it’s an easier process for developers. We will have to wait and see what they actually say if they try this method out. But if it really is this easy, hopefully we can see some of the more popular games out there work on the Steam Deck. In the meantime, you can check Are We Anti-Cheat Yet? for an unofficial list of games that are confirmed, don’t work, or already work with EAC, BattlEye, and other anti-cheat software.