This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Drawn to Life
The first game had Wilfre killing the Mayor and the ending scene, where Jowee left Mari to sail the world like he had always dreamed. A truly touching song played over this while Mari walked around the village, remembering everything they had been through before he left. Of course, he comes back. And to top it all off, your character and the ghost of Mari's father are watching in the distance when Jowee comes back.
The sequel, at least the DS version, is even worse. The entire world of Raposa has just been a dream of the kid Mike, in the real world, in a life-threatening coma. When he finally wakes up because of your efforts, all of the Raposa vanish. Every. Single. One. While Mike, the in-universe one, is watching, and asking why it is all happening in a panic. Now this in of itself is somewhat heart-rending. But THEN you get into actually interpreting what everything that happened in the series actually meant. All of Wilfre's schemes, in all 3 games? They were meant to perpetuate the existence of the dream world... by killing the real Mike. The spreading darkness in the first game? Symbolic of Death. And now this game, the loss of color in the world is symbolic of, what else, death. Not only that, but in the scene in the end credits, you see that Mike's parents died in the car crash that sent him into a coma.
The game starts by having you answer three questions and sketching a picture (introducing you to the drawing mechanic of the game), but you have little idea what the significance is, and Heather makes an appearance speaking in gibberish. It turns out that this was a Book End. The questions were asked by a police officer, interviewing Heather of the events leading to the crash, your sketch is Heather's sketch of what happened, and Heather's gibberish finally comes through to Mike as he wakes up - it's a prayer for Mike to wake from his coma. Just... damn if that's not a heart-wrenching design.
5th Cell themselves even thought the ending to the sequel was too depressing, and actually went as far to change the ending to The Next Chapter in the Compilation Re-releaseinto something much gentler than the ending described above. YMMV whether the ending is better being changed to something a lot more happier or if it is worse because it lacks the emotional powerful sadness of 5th Cell's original ending to the game, since the changed ending leaves unanswered questions, and takes too much of the game's plot out of its original Context for example, there was never a car crash. Instead Mike falls from a tree trying to catch fireflies so Heather's face is shown as just fine and uninjured. The art in the changed ending also looks similar to the Scribblenaut's official game artwork.
Mayor Rose of Watersong being willing to sacrifice her life so that her son can be the next Mayor, feeling she paid too high a price for her vanity. And since she's an opera singer, her last song is conveyed through an actual song.
Jowee's reaction to Mari's betrayal. Even moreso when he later finds out she's Not Brainwashed.