Croteam put out a new blog post going over their latest development work at this Croatian studio. As with most studios in 2017, VR is a big focus and they continue investing heavily in Serious Sam VR: The Last Hope, which is currently in Steam Early Access on Windows. They also confirmed that Serious Sam 4 is still happening. With their VR push, Serious Sam VR: The Last Hope “Shanti” is coming and they are also working on SSVR: The Second Encounter, Serious Sam 3 VR: BFE, and The Talos Principle VR.
Outside of the VR space, they are working on a free update for all Serious Sam games. Their "Serious Fusion 2017" will roll out gradually for all their games and includes supporting SteamOS/Linux/OSX across their catalog of games as well as making use of Vulkan (and at the same time they are ending their D3D9 API support).
Also coming to their Serious Fusion 2017 update is split-screen support, 64-bit executables, multi-threaded rendering, a new save-game system, full support for all controllers, proper multi-monitor support, borderless window support, proper 3D audio, improved physics, texture streaming, better modding support, and other improvements/optimizations. Sounds like a hell of an engine update and exciting to see this land along with their expanded Linux/Vulkan coverage too. Hopefully a lot more Croteam benchmarks coming up.
More details on their 2017 happenings via this Croteam blog post.