This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Zero Punctuation
During his Spec Ops: The Line review, Yahtzee finds himself seriously thinking about what message this game sends. It must be seen to be believed, that he's honestly surprised by the game and the things it makes you do, and how it actually affected him. This is best shown in how he regrets using white phosphorus after finding out it murdered civilians, including children, which he himself is no fan of. It was that disturbing, even to Yahtzee.
Yahtzee: *sigh* Do you remember when shooters were about killing demons from hell? Those were good days.
His review of Duke Nukem Forever (For Real This Time) verges into this territory. You can just tell that when he expects a more mature kind of Duke Nukem game, one where Duke is forced to learn that his actions have consequences, in a way growing up, that he was almost certainly grasping at straws, hoping that it would be good. For the rest of the review, though, he knowingly tried and failed to like the game, to find at least some small level of pleasure as he played it, while aware he was failing miserably at that and eventually admitting that he's "pushed games off subway platforms when they had less flaws than this!". Summed up in one sentence:
Yahtzee: I guess I want it to be good 'cause that's how the story is supposed to end.
He gets a small one at the end of his Silent Hill Downpour review where he admits that constantly comparing the new Silent Hill games to Silent Hill 2 gave him no satisfaction and actually made him a little depressed.
His comparison of the Metal Gear franchise to Lennie in his "Ground Zeroes" review. While he uses this to explain that he can't bring himself to hate it for its shortcomings and occasional screw-ups (since they are not done out of malice), the comparison ultimately gives away his thoughts on the game right off the bat.
"The Warchief died at my hands, and one of his brainwashed bodyguards took his place. Not Khosh, though. Khosh lay dead, killed by one of the rogue captains, although he'd been able to reduce the guy's health enough that avenging his death was little more than a trivial moment of cleanup in the battle's aftermath. But I was genuinely sad. Khosh was dead, having sacrificing himself to keep a difficult opponent occupied so that I could concentrate on the main target. Was this truly the same orc who'd fled blubbering from a duel, moments before I'd taken him under my wing? He'd had a true arc with a heroic end, leaving aside that whole 'forcibly rewriting his free will' business... Talion doesn't get much more than the usual "NOW WE CONTINUE THE FIGHT FOREVERMORE" weak-ass conclusion to send him off with. But I couldn't have given less of a shit, because there was a new star in the sky that night. A little sweaty green one that drank too much."