I agree that the difficulty could use a bit of smoothing. If you don't mind, what level did you get stuck on? I'm planning on releasing a medium-sized update once the jam is over and it'd be useful to know
Viewing post in Chesscourt Mission jam comments
Ah! You actually have to use the rook/castle to get the king past the spikes, and the pawn needs to get another use to get things in place. I should definitely have an easier level with the knight/horse beforehand, because having it be introduced ends up implying it's more important to the puzzle than it actually is.