Glad you're enjoying it. Making it to Level 13 is pretty awesome. I remember one of the early playtesters calling it 'the level from hell'.
There doesn't seem to be a way to both take the f2 king and the a1 pawn. The b6 bishop can't reach either. The d1 pawn can only reach one or the other.
Or I start with dxe, take the white rook with the pawn, and end up with black pawn on a1 and white bishop on e6.
Another hint?
EDIT Oh never mind, finally got there. Just a slight tweak to the move order, which took forever to discover.