Steven Universe – Genocide Run:

-Steven kills all Corrupted Gems he meets, including Centipeedle in episode 1, and all Beach City residents, including Connie who was at Beach City at the time and except Greg.
-When Steven meets Lapis atop the tower, he doesn't heal her Gem, but shatters it in cold blood.
-Garnet confronts Steven about his violent tendencies and Steven shatters her, but not before Ruby and Sapphire bid farewell to each other.
-Jasper and Peridot come to Earth, but Jasper sees how evil Steven is and comes to the realisation that Earth is her home and vows to protect it from him, but dies in the process, while Peridot manages to escape.
-Pearl has enough of Steven's killing and confronts him, but again, is shattered, but not before asking to Steven's Gem "Is this what you wanted, Rose…?"
-Peridot makes a final stand against Steven at the Galaxy Warp, but is shattered, but not before saying "Earth is full of monsters."
-Realising she's the only one left, Amethyst makes one last stand against Steven, doing well against him, but is shattered in the process.
-With nobody on Beach City left to kill, Steven then turns to Greg and brutally murders him. It's then that Rose Quartz appears in his mind and tells him to unleash the Cluster, to destroy the universe. Steven refuses, but Rose Quartz laughs and says "Since when did you think you were in control?" Before unleashing it herself.
Game over

Yeesh, kinda glad it didn't go down that road o_o