It's pretty fun. Basically you become one of those hundreds of random soldiers that Snake snaps the neck of and immediately forgets about, and you fight against other random soldiers to the background music of various Metal Gear games.
You can customize your appearance, face, voice, clothing, etc. Unfortunately you can only be a male character, and unfortunately for all you fans of guys out there, they're all pretty ugly. You can cover them up enough to where you can't tell, though. Still, I'd like to be able to be some hot girl or a bishy boy if I so desired, that's probably my major gripe with the game.
Anyway, then you get to assign various skills like being better with sniper rifles or setting up traps faster to your character. You can equip/unequip these at your leisure, so you can do a total 180 with what your character specializes in if you change your mind. The skills level up as you use them, which makes them improve. My specialty is sniper rifles, CQC, and girly mags, if you're wondering.
The rounds consist of various rules, such as team vs team, deathmatch, capture the flag (actually, it's capture the GA-KO and Kerotan), etc. The best one is Sneaking, when one lucky individual gets to be Old Snake equipped with OctoCamo, and he has to steal a certain number of dog tags from players to win. Unfortunately this means that everyone else is supposed to either kill the other team or Snake, and going after and killing Snake is just sad and I don't want to do it, dammit. I kill the other team instead ;D
I had my first encounter with someone telling me "u suck" the other night while I was playing :D It was... so awesome. See, I don't play online games like... ever, so this was all so new to me. He told several other people they sucked too, but I still felt special.
Oh yeah, krile
was listening to boyband CDs while watching all of this. Did I just blow your mind?
In the end this probably isn't the kind of game I'd bother with if it was a separate thing, but because it's included with MGS4 it's a fun distraction. Plus I think if you try to connect but have some kind of issues sprite!Otacon shows up to guide you through troubleshooting or something. I should really yank out my wireless router and try that.