The game seems pretty polished! Obviously the mechanics work very smoothly, but I would like to offer some constructive criticisms
The fact that I had to hold 2 buttons to move in-line with the grid bothered me a lot. it was strange to move on diagonals of the grid when press ion just one of the WASD
It is not immediately obvious to me why this game needs to be an MMO. It is need that the multiplayer functionality works, but the core game loop seems to be timing and positioning of your character. Unless there are difficult bosses later on the justify multiple people teaming up on an enemy.
It is also not immediately obvious to me how the theme of shadows ties into the game exactly.
These are just minor criticisms on an otherwise very well-made game! Bravo!