Regarding the art style, it's a bit of personal preference and a bit of I think it's hard to see the pieces this way. Maybe add a white contour around the pieces or some perspective effect, or have the contour be a different color from the lines inside. The pieces sometimes overlap and it's not that clear? I feel like the King and Queen looks a bit too similar, the knight could be facing sideways (like its usual representation) to be more visually clear. I think in general pieces could have a better silhouettes but heh. Or maybe different colors or use gradients or make every piece shorter.
I just feel like here for example it's kinda hard to read.
Also lol you can really take every pieces with just the Warrior piece only, even in hard difficulty.