This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Dead Rising
Dead Rising pits you against many psychopaths as the game progresses. Most of them are just normal people who snapped and went crazy when the zombies arrived, and the player must kill them to protect other survivors. One of them is a crazed Vietnam veteran carrying a machete, who wanders around in a hardware store. Only after fighting and nearly killing him does he reveal that he has been suffering from flashbacks to Vietnam the entire time. While this was obvious to most players, what he revealed next came as a shock: He had been out on a shopping trip with his young granddaughter when the zombies arrived, and he watched as she was torn apart and eaten by zombies. He tells you this as he hands you his wallet with a bloodstained photo of his family. After his granddaughter died, his vision "flashed white" and he starting suffering from flashbacks. He tells you this after you, the player, have just ensured his death.
Adam the Clown is simultaneously tragic and horrifying, having gone insane after witnessing his audience (which would've included children) getting eaten by zombies, and convinced that running the Space Rider roller coaster at breakneck speed will keep the zombies at bay to the point that he's willing to kill Frank over it.
Ending A, watching Frank fall down in defeat at the Helipad while he gets swarmed by zombies... thank God for Overtime.
No wait, forget Overtime, that ending is worse because it seems Isabella and Frank are both completely screwed. It seems like a massive Player Punch at first, though it’s quickly revealed in the epilogue, through text, that Frank survived along with Isabella.
In ‘’3’’, it’s revealed that Isabella made a deal with the devil with Phenotrans by giving them the antidote recipe and was unable to give out the permanent cure, and that she was unceremoniously kidnapped under the Phenotrans CEO's orders.
While he was an insane asshole, Carlito clearly had some good traits, like his love for his sister. His death is fairly sad, especially because he was taken out not by Frank, but by some random Psychopath.
If the act wasn't so mind bogglingly stupid, you'd feel bad for Lindsay when she frantically tried to save her dog from the zombies. Even though they were clearly disinterested and the act only allowed the entire horde to enter and overwhelm the mall and the survivors within the entrance.