I would also like to point out that if the game runs then it is an ok distro, imo.
As for performance, the more tuned your setup is then obviously the better the game will perform. As in "tuned" I mean, using a distro with a custom kernel (possibly compiled by the user), also using flags when compiling for your specific cpu. Another thing that will help out the bigger distro's is to disable services that are running in the background.
Gentoo is very customizable and would be good for more knowledgeable users. If gentoo is to far out of your grasp yet look at other distro's like Arch that are i686. It's still optimized but lacks some of the optimizations that gentoo has. Basically work your way down from i686 to i386 based distro's.
Also remember, each person has a personal taste of what they want from there system. So two distro's that use i686 are basically the same optimization wise, (unless the user goes further with there own compiles), but one may be more to the liking of a specific user and not another.
There are many other things to consider also beyond how optimized a system is to determine overall performance. One example would be how up to date is the software you are using? Sometimes one little piece of software that effects SDL or glx or a dependency the game relies on can greatly effect overall performance also.
Hopefully some of this is usefull. Also i may be wrong on some stuff so if I am someone please correct me.