Based on the EDuke32 game engine, NBlood is a new open source port of the classic FPS Blood. From what Voidpoint (Ion Maiden) said on Twitter, it's using their version of the game engine too.
OpenMW, the excellent open source game engine for Morrowind has made some interesting progress towards supporting later games like Oblivion, Skyrim, Fallout 3 and New Vegas.
Regular readers will know by now how much I've enjoyed using Lutris to bring together my game library across Steam, GOG and more. It just recently put out the big update!
On top of AuroraRL shutting down this month, Coregrounds a competitive strategy game that pulled in elements from both Tower Defense and MOBAs has also shut down. This one has also opened up the code.
The difficulties of game development and Early Access have hit another developer, with Sun Dogs throwing in the towel with AuroraRL. It's not all bad news though.
At the start of this year, I gave a little mention to vkQuake2, a project which has updated the classic Quake 2 with various improvements including Vulkan support.
If you have one of the more recent NVIDIA RTX graphics cards, here's an interesting project for you to try. Q2VKPT from developer Christoph Schied implements some really quite advanced techniques.
I have some pretty fond memories of playing Wolfenstein: Enemy Territory online with friends many years ago, so to see it still alive and kicking with ET: Legacy is awesome.