I like the concept! It's neat to incorporate chess and warp the rules a bit!
I did find that the optimal strategy quickly became just moving left and right and spamming the spacebar which wasn't too engaging, maybe something to spice up the shooting to encourage timing and positioning? Some super bouncy dice which you'd want to shoot at the sides to bounce as much as possible, or some powerful die which explodes so you'd try to wait a bit for enemies to group up, maybe? ,,,I'm just throwing around ideas, they're probably not great examples haha
Still think it's a neat game! It's definitely got an atmosphere to it!
Also, got a score of 268 myself! ,,,dunno if that's good!