So, I'm in...
...though I don't know if it'll be an actual game when I'm done. I'm hoping to get something working with Vulkan, but that means a lot of boiler-plate work before you can do any rendering - plus I'm flying from the US to the UK tomorrow.
Aiming to get a little animated/spinning planet, will see how much I get working graphically and then worry about gameplay.
Oh, and I'm using C#/Vulkan, with maybe some GIMP/bfxr/Abundant Music.