Great concept! controlling one player with the wasd and the other with arrow keys could make it more intuitive for switching in between and open up co-op opportunities. When you add different levels seeing it from a little bit further back could be helpful as well. 

Nice use of the trail renderer with the movement, gave moving some feel. I also liked hearing the soundtrack switch as I switched between Heaven and Hell. I wonder if the level design could benefit from more verticality to mix up the moving left and right for long periods.