i thought the sp and mp were both good, there was never no real support from ubisoft for the mp game and the game had its share of problems when it was released log in servers going down alot (sometimes for days),maps not being able to be downloaded,long que times for games etc...i think it put a lot of people off but patches and download fix's came out an things got better ,mp mode has a few different match types Team Deathmatch,Capture the Flag etc ..
heres a review for it http://uk.gamespot.com/pc/action/farcry2/review.html