Don't really want to root my phone, but thanks for the tip about Market Enabler anyway. I guess it must be US-only for now? Hey, at least I bought it before they realised they'd made a mistake - it's just annoying because I'm still on a basic 4GB SDHC card and wanted a bigger one, but I don't want to lose any apps by trading up...
It does run very well on my Desire, though. Some slowdown and glitches on very fast corners with several cars on screen at once, but not that much. It's still really playable - it'd make a pretty good regular game on a PSP, let alone a mobile. If you can find it on the market I highly recommend it.