Unless you have a quad and über graphics card, anyway. On the lowest possible graphics settings, on a small map with only a few AIs, it's so slow and jerky as to be unplayable on a G5 iMac (last revision before Intel iMacs). From reports I've read elsewhere, it's hardly any better on a brand new Macbook Pro, Apple's best hardware aside from the Quad.
Oh yeah, sound and most animations also don't work.
Want to try turning up the graphics and play on a huge map with lots of enemies? Good luck, there's no Mac out yet that'll handle it.
It's one step backwards for Mac gaming.