WARNING: Spoilers ahead!
Of all the games that came out in 2007, none brought us as quite as close to their characters as The Darkness did. The game's horrific violence was punctuated with oddly endearing loading-screen monologues and a tender scene in which its anti-hero just hangs out with his girlfriend on a couch, all of which made Jackie Estacado - a former hitman who'd become an unwitting host for a parasitic demon - seem less like a gun-toting murder machine and more like a real person we knew.
So when The Darkness itself - which up until that point had been little more than the creepy source of Jackie's demonic superpowers - turned traitor and forced him (and us) to watch as everything he cared about was destroyed by his worst enemies, the game didn't just tug on our heartstrings; it ripped them out of our chests and devoured them. If you need more elaboration, the video below shows exactly what we're talking about; just be warned that it gives away one of the biggest plot twists in the game.
BioShock's mid-game revelation might have turned everything you "knew" on its ear, but it still didn't pack the same emotional gut-punch as The Darkness. Even so, anyone who played through it was haunted for weeks afterward by the words, "A man chooses; a slave obeys!"