Lyric discussion by wh1telighter 

Cover art for Happy Birthday lyrics by Birthday Massacre, The

What I can imagine.. she obviously has a broken state of mind. She goes to a party of one of her friends, but her other 'friends' (the voices, that only exist in her mind) tell her to kill the people at the party. Or maybe she doesn't even realize she is the one killing them, I could imagine her seeing her 'friends' murder the people, but she also 'taking part' when they tell her (stick in the back of her head, I guess a knife or such). But then the 'ghosts' of her dead friends are chasing her. Also 'Don't forget the video' I imagined her taking a photo/video with her 'friends' but obviously she is the only one appearing on them. Well this is only what I imagine.

My Interpretation