All of our recent releases and updates to games will have support for Retina displays, this will include any game released or updated since May 2013.
Performance will be affected if running at the top resolution, although we believe that the games still look great at slightly lower resolutions that are available. In an ideal world, all games would run at 120 frames per second at full Retina resolution, but the graphical output will always be affected by the hardware. There are several Retina machines now available, with varying graphics card abilities.
In short, Retina display will be available for new releases but will directly impact performance. If using a Retina machine, please consider the power of the machine and graphics card when adjusting video settings.