I'm going to ignore Lost Odyssey and talk instead about the entire second playthrough of Nier, which I completed recently.
"What?!" I hear you say, "Nier? That game that had a couple of very sad moments but I would definitely not consider a very sad game?!" You say that because the developers made a fatal mistake, and at least some players probably missed a massive, massive part of the game. If you wait 'til the credits finish after completing it the first time you're given the option to save, and if you do so and reload that save... wow. Wow.
You play through the game again, starting from about halfway through, and get to see the game from the perspective of the shades. At several points in the second playthrough it cuts to scenes involving the four bosses between then and the end, and also subtitles appear at the bottom of the screen when shades talk, so you can now understand them (although the characters still can't). And... wow. Never before has a game made me feel like such a prick. Turns out things aren't quite as you thought, and it really paints you as the game's villain, as you do some pretty goddamn awful things without realizing. What makes it worse is that on your first playthrough you just stormed in and cut down the bosses like you would any other enemy, and then when you see what you did on the edited playthrough... yeah, you're all dicks for playing this game. The Shadowlord is easily one of the most tragic game villains of all time, and this game seriously deserves more recognition.
The game impacted me so much it's unbelievable. I still haven't gotten over it. If Yahtzee played the extra playthough I think his review would've been much different.