What single 100% completion are you the proudest of?

[Awexsome]

I usually don't complete games to 100%. Some games I get really close (One more playthrough of Tales of Vesperia should do it) but I have gotten through every Halo game on Legendary. Solo. Even Halo 2 with all those jackal one-hit-kill snipers.

 

[Nydestroyer]

assassins creed 1 without a guide...so many flags D::::

 

[Twilight.falls]

I complete every game I own 100%. Even if I don't particularly like it, I feel obligated to increase my credibility when I talk about games.

That being said, I've cleared Final Fantasy 13, that was truly a titanic undertaking. Donkey Kong Country Returns, Twilight Princess, Majora's Mask, Ocarina of Time, Super Mario Galaxy 2, Fallout 3, God of War 3, and Red Dead Redemption are the games I've most proud of completing.

Edit: And Kingdom Hearts 1 and 2 on Proud difficulty. That took a while as well.

 

[Pingieking]

Valkyria Chronicles. Getting every single medal in the game was a challenge, but I did it.

In fact, if it weren't for the ability to save during battle, I don't think it would have been possible. Especially for the Expert skirmishes.

This. That was actually a really hard game at some points.
I got the platinum for Dynasty Warriors 7. It was a bit soul crushing, but I've always wanted to complete a DW game.

I know someone who 100% Yakuza 3. The Japanese version. That blew my mind. I played ~50 hours, finished the story, and I was at 24% completion (the story accounted for maybe 10%). And I was playing the North American version, which doesn't have any of the host club stuff. The host club is the most annoying stuff too; all those women and their demands. Some of the side stories are really hard too.