DELETE THISSS

mouse camera controls and centering the camera rotation around the player would be an immediate improvement,
but keeping the arrow key controls might be the way to go if you opt to only have a few set camera angles (like 4 isometric views) so you cant just go from anywhere to anywhere. Its what Fez and Monument valley did, and I suspect level design will be significantly more difficult if you don't have a similar restriction.

The line dissapearing effect is pretty seemless, I thought it was just a shader artifact when I first saw it.