Loved this!
Even if sometimes the controls feel a bit weird and the attack was difficult to manage, I loved the idea of changing "plane of reality" and the fact that every level has to be solved in both "planes": killing all the enemies in the dungeon and displacing elements on the chess board. That's some very good game concept!
Plus, the fact that you used completely different art styles (2D versus 3D) fits perfectly with the idea! Great job :)
Ps. This is one of the few games I was able to complete. I'm kinda crying now. Thanks :')