This is an interesting variant.
When black pawns reach rank 1, they become white bishops! I’ve yet to find what black gets out of this. I unlocked the serpent, which was an interesting, distinctive piece. It wasn’t immediately obvious what you meant by “ladder pattern”, but I soon learned that they can move diagonally and orthogonally one square, but I couldn’t bust the black serpent diagonally out of the bishop’s starting position without first moving the pawn. So I’m not sure I really understand it, yet.
All the pieces looked good and I appreciated not having to spend hours beating a chess computer to try out the mechanics. Could you even code a computer to play this, well? It’s very novel.