I played the first Halo game and beat it. I was pretty young and didn't die often, which was saying something for the age I was. This was on the PC, of course, since it was made by my bros and dad. It ran better than the Xbox and at higher settings, and I played games on it whenever I got the chance. (lol spoiled kid)
Anyway, Halo 2 came out and the PC port wasn't scheduled to come out until months later (from what I remember). I wasn't eager to use an Xbox as a gift opportunity just to play Halo 2, since the original never held my interest for more than a week or so.
A while later, I played it a bit at a friend's house, and I don't remember it being too much different, other than the fact that I was considerably bad at it because of the fact that I was aiming with thumbs as opposed to a hand. I was pretty turned off at that point, and never payed much attention to the rest of the series afterwords.
I guess I was just a spoiled Valve kid who would rather play Half-Life on his supercomputer rather than Halo on a console. The game was neat and all, but I just had other things to play. There's also the fact that I get more satisfaction from solving a puzzle in a game rather than just running into a room and shooting anything that moves.
I guess I don't understand it much either, so I guess I'm just not a Halo guy.