I try to finish all my games
Super Mario Sunshine - Finished it three times, got all 120 shines each time
Luigi's Mansion - Finished it 6 times, such a fun game
Timesplitters 2 - Still havent gotten around to finishing the story mode, finished most of the challenges and arcade mode though, loads of fun single player and multiplayer
Metroid Prime - Finished it twice, second time through was on hard mode, couldnt be bothered getting 100% though
Super Smash Bros Melee - Logged well over 300 hours into this gem, need one more goddamn trophy, awesome game. My most played game on Gamecube.
Wave Race - Done everything, unlocked everything, excellent racer, still play it every now and then
Resident Evil - Finished it 6 freaking times, played it to death, to unlock all the costumes, weapons and such, one of my favourite games all of time
Resident Evil 0 - The end part ruined it for me, still havent finished it, im stuck on some retarted boss that takes 30 minutes to get up to from my save, and i just die straight away, stupid
Eternal Darkness - Currently on my 4th play through, such an incredible game
Starfox Adventures - Finished it 3 times, loved every minute of it
Sega Soccer Slam - Havent quite finished this one yet, only just got it though about 1 or 2 weeks ago
Sonic Mega Collection - I play this nearly every day, its all my favourite games as a child, in one game, priceless fun
Mario Party 4 - This game can kiss my ass, played it about 6 times, boring get, my least favourite GC game
Rogue Leader - Same as Mario Party 4, except its my second least favourite GC game
The Legend of Zelda: Wind Waker - Probably my favourite game of all time, finished it twice so far, eager to play it through many more times. But i hate that stupid Nintendo gallery, tedious get, i dont see the point in doing it if its not fun, which its not, for me
Pikmin - Whoa, challenge mode has provided me with unlimited replay value, its so god damn addictive and fun. Plus ive finished the normal mode many times
Super Monkey Ball 1 and 2 - Awesome! Addictive! Finished everything in both of them! Except master mode, which is impossible to unlock

And thats just the GC games

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Heh, yeah, i guess i just love games, which is why im at a gaming forum after all isnt it?