"If you want to get some of the now finally available games for Linux, KDE Plasma should be your primary choice to enjoy the game. I have also heard of users switching to KDE Plasma because we still provide non OpenGL based setups," Martin explains in his Fallback mode in KDE Plasma Workspaces blog post.
His blog post shouldn't be a big surprise to faithful Phoronix readers keeping up on the latest compositing window manager and OpenGL driver developments on the Linux desktop. As Canonical gets rid of Unity 2D and forces using to use Compiz+Unity, GNOME Shell dropping its fallback mode, and other pushes towards requiring OpenGL support and a compositing window manager, KDE isn't seeing any major shifts.
KDE Plasma with KWin will still happily run with its non-composited X Render back-end and everything will be happy. There's less overhead this way and it's easier on uses with older hardware and for cases where there is no OpenGL support; not all Linux users want to toke on LLVMpipe.
Speaking of desktops, if you happen to be a current GNOME user, be sure to participate in the annual GNOME User Survey.