Back in March, Crytek started offering its Cryengine V game engine to developers on a "pay-what-you-want" scheme. Today, developers don't even need to go to the trouble of paying $0 for the engine to check it out. The source code is now publicly available on GitHub.
According to David Kaye, Crytek's senior systems engineer, the company moved the code to GitHub for a couple of reasons. First, Crytek wanted to make it easier for users to see the differences between one release and the next. Second, the company wanted to make it more convenient for users to keep up to date with new Cryengine releases.
The code might be publicly available, but Cryengine doesn't use a common open-source license. Users must agree to a limited license agreement, which states that Cryengine cannot be used to develop anything other than games. The code can't be used for military projects, gambling, science, architecture, or what the license somewhat amusingly calls "serious games." By that, Crytek means things which are technically games but "not developed for the sole purpose of entertainment." The company cites examples of "training, simulation, science, architecture, etc."
The open-source project still has some work ahead of it. Crytek is working to make it simpler for its internal version-control system to accept pull requests from GitHub. As users start digging into the code, it'll be interesting to see what projects develop out of Cryengine and its Marketplace.