This game is epic, and the music is super catchy too! Only complaint is that the flying-with-gun-and-steering-with-arrow-keys is a lot more difficult on a laptop.
My way of viewing this is sort of him going through his depression, manifest by these monsters. First he is confused, and he can't really believe she's gone. Then he's angry, slaying monsters. When he finds her, he's in denial, believing he can get her back. The "don't look back" part is two things: him blaming himself for her death, and him believing that if he does everything right, he can get her back. Great game, mny shades of meaning, 5/5.
I know many comments are about the multiplayer, but I wanted to add my voice: put the multiplayer on Kongregate... or at least take all the many references to multiplayer out of the game description.
 "Sushi Cat 2"){kind=icon}
 "Tasty Planet"){kind=icon}
 "No Time To Explain"){kind=icon}
 "Fancy Pants Adventure: World 2"){kind=icon}
 "Don't Look Back"){kind=icon}
 "Canabalt"){kind=icon}
 "Exit Path"){kind=icon}
 "Monster Slayers"){kind=icon}
 "the Flood Runner 2"){kind=icon}
 "Final Ninja"){kind=icon}
 "Raft Wars"){kind=icon}
 "Push"){kind=icon}