Nice! Ponies for the win!
I'm missing the checkmate on your second win - the one where your rook has the king in check and the pawn restricts the king's diagnal movement. What's preventing the king from moving one step forward. I'm not seeing a support piece for that manuever. I've forgotten the rules for en-passant, but I thought that the rule only applied to pawn verses pawn and was on the fifth row and not the sixth.
If you look closely, the black king is obstructed from moving one step forward by his own pawn.
Cheers!
Rick...