Amy's full name, Amy Rose, is a reference to the Sonic the Hedgehog character with the same name, Amy Rose.
In Herobrine Origins Part III, Gavin's phone ringtone is the Spider-Man theme song, this was a reference to Gavin's actor, David Figueroa who plays Spider-Man in EliteProducitons' Spider-Man: Dawn of Carnage series.
No one is quite sure if Steve is a hero or a villain. Will Evans, the films director has said even he isn't sure what you would call him.
Though never mentioned in any of the films, Jack Briggs does posses the Brine powers, but it isnt as powerful as Steve or Robert's powers.
Robert's roar that shatters the windows in Herobrine Origins is the exact same roar used in Herobrine 2 - Return of Darkness, one of EliteProductions' first machinimas.