Really nicely presented game. Visuals, feedback, music, style etc etc. All really nice.
Unlike others I was into the character controller movement. Felt nice to me.
Only gameplay complaint is that sometimes it was hard for me to tell which layer I was in when falling. In theory I should know anyway because I should be planning ahead when I fall into spikes, but still it caught me out a few times. I think the blur is not enough. Changing the other layer to black and white would work for example, although it might spoil the style.
In terms of topic, I think it's a bit muddled. Some killing actually kills me (falling into pits), some killing doesn't kill me (arrows); therefore it's not killing so it might as well be a "dimensional portal". I did enjoy when you played with that by having an arrow send me to my death by fall.