Hmm... let's see. Oh! One of the first games I ever played that really got me hooked was Disney's Hercules on Playstation One. I remember I had a notebook where I would write down the codes for each level (this was before save games :P). I played the level where you fight the Hydra a hundred times!! I remember the length of the game was different depending on which difficulty you played it on - on the hardest there were three extra levels. I could never beat the last one, even with my dad's help. Managed to get my hands on it again a few years back and I beat it in minutes

Love that game.