4. Its Characters
None of the actors could have given such brilliant performances without brilliantly written characters to feed off of. Johnson's writing is exceptional, crafting separate story archs that invest us in each character whilst linking them all in ways which further the narrative. Keeping similarities in characters that are the same whilst also giving them believable differences helps keep the film fresh and surprising throughout. The films emotional core is what helps raise it above other high concept sci-fis and the characters that Johnson creates are vital to that.
Where Other 2012 Films Failed: Prometheus: The fact the only characters whose name I can remember is an emotionless robot who shares the same name as my uncle doesn't say much for how interesting all of the others are.