Come on, it's Fumito Ueda and Team ICO. Moments where you will cry are bound to happen.
WARNING! Spoilers Ahead!
- After the fight with the armored beast, Trico is injured enough to be borderline comatose, breathing heavily and barely able to even eat barrels. Even though it eventually recovers, by this point in the game this is the most vulnerable and helpless Trico has ever been, and it's guaranteed to make you suffer for the poor thing.
- The Bittersweet Ending. The wounded Trico finally gets the boy back to his home village. Unfortunately, with the villagers still remembering how this beast had stolen one of their children, they are still hostile to the injured creature. However, Trico is unwilling to leave without making sure the boy is okay, and roars at the other villagers. Having come to, the boy—and by extension, the player—can do nothing but send Trico away for its safety, and it reluctantly complies.
- Early in the game's development, Word of God said that the ending would be sad. This led to people speculating that either the boy, Trico, or both would die. The Bittersweet Ending above disproved all three, and proved that no one has to die to make you cry at the end.
- The look and mournful howl Trico gives as he watches the boy being carried away from him. You can practically read the "Goodbye..." on his face. Augh.
- Meta: It didn't take long for "Reaction" videos to be uploaded of gamers crying at the ending.