Aight ..heres the deal.
The retina Mac will have no problems playing any games, obviously you're not gonna be playing competitive BF 3 with ultra settings at 100FPS + with 3 external monitors, but if you really want that you're an idiot for even considering the mac.
The retina Mac is for video editing, photo, 3D software and so on, and some people who does these kind of things also play games, and that is no problem at all, this laptop can handle it, it's a good all-in-one laptop, especially considering the wight and thinness of the product. Yes the retina display will bottleneck the GPU if you go native resolution, but guess what? you can go 1920x1200, or lower than that and it still looks great!
If you want everything maxed out, build your own computer, it's really not that hard to think. Alienware isn't exactly cheap either, and no offense, but they are darn ugly, and yes, design matters to people, not just performance.