Very interesting concept! Haven't seen anything quite like it.

The unfortunate thing is that I really found no use for the knight.
With the controls being as they are, trying to dodge with the knight is much slower than dodging twice with the king.

I think it might be interesting it the controls were fully with keyboard. ASD to change pieces, arrow keys to move. idk :D

The concept is really cool and unique, would like to see this game get developed further and add more features.