The main developer behind the "dhewm3" Doom 3 engine open-source project shared over the night within the Phoronix Forums that he has been playing around with Wayland. He ended up making improvements to the SDL 2.0 Wayland video driver and now he has his open-source engine with the Doom 3 game assets working atop Wayland/Weston!
Embedded below is a WebM video of the open-source Doom 3 game running on Wayland. The video was done using Wayland's nice video capturing support.
Hit up this Phoronix Forums thread for more information on the dhewm3 engine from the developer himself.