Call of Duty 2 is a well ported game to the Macintosh. Despite its compatibility problems, it still holds itself well.
I must say that Call of Duty 2 provides a great FPS experience. In-fact, the experience is only somewhat short of a cinematic experience which leaves you quite involved.
You'll be operating just about every weapon available during that time. You'll be onboard tanks, trucks, and other moving vehicles. You'll be able to operate many types of artilleries, including mortars, stationary machine guns, etc.
One thing you will not be able to do, is pilot a plane. You are going to be a ground unit for the entire game. The game keeps quite true with the timeline of WW2 as well.
The Mac port is thirsty for an upgrade. I wasn't able to use detail texturing due to EVERYTHING being glazed with shinny bit mapping. The water also looked odd most of the time, with heavy graphical glitches. I played this on a 2008 Mac Pro with a 8800 GT.
I haven't been able to play multi-player yet, but there seems to be many modes, so I would guess that it would not be lacking in that department.
Despite these minor flaws, I was able to enjoy Call of Duty 2. It's been one of the finest war games I have ever played, let alone, liked playing.