Lyric discussion by ZaiVesper 

Cover art for Sunset, 1989 DEMO lyrics by Swimming With Dolphins

I think it's all about suicide.

"You never heard me knocking on the door I found you balled up on your bathroom floor"

The friend of the one committing suicide is trying to stop his friend to do such act. But then, his friend doesn't listen to him.

"You told me everything in your defense And never understood the consequence I won't console, when you have control Every time's the last time, but I know you'll go and do it again. Yeah, you'll do it again"

I think he/she is trying to commit suicide by hanging herself. The halo is actually a rope or something.

"There was a halo resting above your head then it slid down Around your neck and I bet you thought I'd never find out 'cause You think you're so clever"

The friend tried everything he could, but he did nothing. It's too late. But he promises that this won't happen again with his other friends.

"If there's a cause, it's already lost 'Cause I tried the last time and you tossed me aside again But it won't happen again"

My Interpretation