This game is very fun. I love the mechanics and puzzle-like nature of the game. And I love the unique design of all the pieces. I hope more comes of this game, I would love to play more levels and explore the mechanics further!
I think that the game would benefit from more clarity/contrast in the graphics. For examples, walls and pits are somewhat difficult to distinguish. And also, maybe some kind of grid background to make it easier to predict the movement of diagonal pieces across pits.
My only other comment is maybe including some way of indicating which pieces can hop over walls and units and which can't.