The first game i remember of make me proud of beat is The Legend of Zelda: A Link to the Past. That the first big game i beat, and it's not just reach the end of the level without dying, there's a whole history behind that. When i beat him, i was in 6th grade. I was so happy, that i even used "i beat link to the past" to hit on a girl. Didn't work, of course, but still... that game make me really proud.