Perhaps it's the satisfaction of seeing how much you've improved since the last time you played through the game? You probably did much better, maybe even found things you didn't find before, or at least got things faster.

I guess that could be part of, the finding of hidden stuff, because there was some fairly cleverly hidden stuff in there. I guess with that too I could say I enjoyed the music more the second time through.

For me?

• World Of Goo. I first played it when I was, what, 12? It was way too difficult for me. I played it again when I was 15, and I thoroughly enjoyed it!
  I wanted to say PvZ and M&L:BIS, but I really just enjoy them the same every time I play them.

CowLaunch you have the best avatar.

A game that was better the second time I got into it was Wind Waker. The first time I was really young and could not for the life of me get past the barrel scene in Forsaken Fortress, but when I came back to it years later I was simply blown away by how beautiful and brilliant almost everything about the game was.

Almost any example I can think of I didn't actually finish the first time (like TWEWY or Megaman 64 or Halo 1).

Oh wait. Star Fox 64. I always really liked the game but every time I played it I liked it more until like the 20th playthrough or something.

I can't imagine enjoying Ocarina of Time more the second time, even with the 3D version. Interesting.

Thought of another: Advance Wars. I was new to the genre, and this entry level strategy game was more satisfying for me to play a second time.

Megaman ZX: Advent gets my vote for now.

Mario Galaxy.

Just yesterday I started going through the Subspace in Brawl again without my bro, I find it much more enjoyable now.

Super Mario 3D Land. Didn't play it twice intentionally (I'd accidentally let a Super Guide block appear and lost the sparkling stars, so I did the whole thing again to get them back), but it was fun to play it again.

Super Mario 64 DS, which I played through quite a few times and enjoyed every time.

Pokemon Red and Blue, mostly because I experimented with new things like teams and strategies.

Luigi's Mansion, which I must have played through about 20 times. Enjoyed it each time.