I think this is the game I've played the most in my life(?)

Red Dead Redemption: Chad Version

Great to beat the campaign with a friend, but it kinda sucks if you play by yourself

This one is the best "2D style" Dragon Ball Z game of Ps2.
I forgot how many hours I've spent playing it with my friends in my childhood... Golden times that won't come back...

Great game, but in my case I had a better time playing co-op with friends than playing the game content itself

One of my favorites of all time. I'd even go further and say it's my favorite ps2 game.

I think I beat the main campaign 30 times or so

I didn't play as much as GOW 2, but I actually think it is a great game as well