I gave the game a try just for benchmarking. /geek I haven't see any graphical issue with Metal, on the benchmarks at least. The most relevant comparison between APIs should use settings where the GPU isn't the limiting factor. On my weak intel HD, this is only possible with the very lowest settings and resolution. In these conditions Metal is at least twice faster (97 min fps vs 43 min fps). I cannot use the average fps for a fair comparison since it's capped at 120 fps on Metal (limitation of core animation). The average fps of openGL is 70.