Mass Effect 2, I played the first 4/5 times but the second over 10 (and the third 2 times) because I don't know, I wanted to test things and because I liked it so much.

God Of War 3 too, because I wanted to platinum it ô/ Must have finished the game close to 10 times too (before I moved out I also finished TLOU 3 times but had to stop, was on my way to fourth and more).

And as someone said above Prince Of Persia WW, because it had the Sandwraith and some cool story, but most of all badass motherfucking Dahaka with metal/rock music, what else!

I've played Mega Man 2 enough times to beat any robot master first (although I still use the pause trick to beat the boss in Wily's Castle 4, I HATE that boss).

I've played Battletoads enough times to actually beat the game (without using any warp portals).

Yeah.. nobody is gonna believe this... nice try..

Maybe Crash team Racing for me.

Super Mario Kart Battle Mode

yes soul calibur 5 itill play it ,so good the online

Me and my bro have become almost zen masters at the last of us, although grounded and its less frequent save points are proving to be hard as fuck.

tekken tag tournament I learned every combo from all 30+ characters and I was literally unbeatable.

ridge racer type V played it for over 10 years non stop and I probably have best fastest lap and course record in the world

Most probably Sonic Adventure, though I sometimes forget what to do even after so many years.

Age Of Empires 2.

greatest PC game I have played in the younger games.......played it for a few years at least once a week - stilll got it working! without online...which I never played tanyway :(.