5. Counter-Strike (PC)
Although it was an internet game, me and my friends have had a lot of fun with this game. Especially when using 'Roger Wilco' or something like that: after the first one died, he would see where the enemy was and give hints to the one left alive.
4. Super Smash Bros. (N64)
I've never really played it with my friends, because they think it's 'kiddy', but I've played it often enough with my brother and some of his friends. Great game, although I still remember some guy that beat me with Pikachu. With Pikachu!!
3. Half Life (Decay) (PS2)
Decay of PS2's Half Life is so cool. Nothing better than taking out ugly Aliens together! And the fun we had with blowing up the guy in the wheelchair....
2. Golden Eye (N64)
2vs2 or free for all... what a great game! I always kicked their ass with grenade launchers in Archives, until they didn't want to use that weapon anymore.
1. Perfect Dark (N64)
I don't know how much multiplayer time we spent on this, but it has to be over 50 hours. To avoid fights with eachother, we played against bots most of the times. And the cooperation game was so sweet!
Actually I've played it yesterday.
