I have a Mini and I found that some games (such as Sims2, Sims2 Pets and AOE3 work) but others (Later Sims2 upgrades and NWN2) do not. This is due to the onboard Intel graphics.
I did find either a Widget or a Website which listed a lot of games and indicated whether or not they would work on my Mac - but I can't remember what that was.
If anyone can point me at that Widget or site please I would be grateful.
I have also got some games to run using the PC versions with Crossover. These include GuildWars, Starwars Galaxies and the PC version of NWN, including the two updates. I can't find the Mac version of NWN (it seems to be out of stock everywhere) - but this is expensive compared to the PC version. Not tried the Linux version of NWN yet. Anyone know if that works please?
The best game I have found so far on the Mac is World of Warcraft - the same box includes both PC and Mac versions. This installed and works fine on the Mini.
Edit - I tried the Linux version of NWN, running it from a shell command line as for Linux. It didn't work. Surprising since OS X is essentially Linux under the GUI.