10. Shadow of the Colossus
Animal cruelty is the worst kind of cruelty. When Wander’s trusty steed Agro falls of a cliff and (seemingly) dies before the final Colossus, that was a horrible scene to behold. Not that Shadow of the Colossus would have been too much of an happy game to that point, what with Wander starting to rot alive more and more with each subsequent Colossus.
And then when all is over, Agro comes back. And the girl is alive too! Just… Wander is dead. Or reduced to a horned infant. And Agro has a broken leg. Everyone is sad. And the players confused if this is now a good ending or not. Spoiler, it’s ambiguous.