I find it interesting to make low-graphics 3D-games for Raspberry Pi, like with low-poly objects and locations, simple (.jpg) textures, has anyone made something like that?
I made a research and found out a game engine called Urho3D(website), that supports making game for ARMv6, ARMv7, ARMv8 processors and Raspberry Pi, so it will make it possible to make games even for RasPi Zero (1GHz ARMv6, 512MB RAM), what would be actually the cheapest gaming platform ever with 3D graphics.
As for game engines, I know that RasPi Zero runs id Tech 3 engine swiftly (that is also known as Quake 3 engine), and games like Quake 3, Assault Cube and so on, but Urho3D can make things with much better graphics that require less resources, which is useful on low-resources devices.
It is but you will not be able to do much without a GPU, even those games will not run on WOA. This is because of lack of GPU support, the cpu is doing everything and being god slow at it.