I Love You... I'll Kill You

This song is about internal emotional/psychological turmoil. It is about the good and evil in your soul battling with each other and preventing you from having a real relationship or a healthy emotional state.

/Don't play games with the ones who love you/ /Cause I hear a voice who says I love you, I'll kill you/

This part references your subconscious telling you to be wary of the dangers you may face getting romantically involved with someone else with whom you already have a stable, friendly relationship (either that or messing around when you've already got someone). You hear an inner voice warning you that it loves you too much to see you face such danger and will kill you to prevent you from being emotionally brutalized by failure.

There may also be a double meaning here as this part may more plainly reference a real lover wishing to hurt you if you wrong them. Love and hate come from the same place, so in their desperation they may commit a "crime of passion" against you if you commit some sort of egregious romantic transgression.

/Look into the mirror of your soul Love and hate are one in all/

Now the song shifts to deeper introspection and you are invited to look into your own soul, revealing that love and hate are "one in all", or two emotions stemming from the same source. One cannot exist without the other.

/Sacrifice turns to revenge [...]/

Contininuing with introspection, I believe this to mean that the sacrifices you make for others (out of selfless love for them) causes you to take revenge on yourself (out of self-hatred). This could involve many different things- trusting someone too much and being burned, giving someone too much of your heart and seeing it crushed, basically just making a decision which hurts you in the end no matter how much it makes you feel good for helping them.

/You'll see the face who'll say, I love you, I'll kill you, But I'll love you forever/

In contrast to the earlier iteration of this line, this iteration is said only to the self by the self. You will see the face inside you (your psyche, perhaps). Although you love yourself, you will inevitably hurt yourself because of the actions you had taken in love. Again, "love and hate are one in all". But this iteration adds the last line which is very interesting: "But I'll love you forever". Even though you are constantly killing yourself inside over the emotions that get you into trouble, you'll always have yourself. Always. You cannot depend on anyone else to be there for you- especially when there is a war raging in your heart. Trust no one.

Even when you are killing yourself, you are doing it out of self-love, preventing yourself from getting hurt again by someone else. And that's why:

/Loneliness, I feel loneliness in my room/

In the end, when you are being held hostage by the self-hatred in your heart telling you to distrust yourself and the self-love telling you to guard yourself, you will be alone- but you'll love you forever.