turn foes mistake to an advantage
I'm not sure I understand this. Is blacks first move the mistake? Blacks proper response to h7 is Qb7 then capture the pawn on the next move.
Yes, there are obviously plenty of mistakes; but if there are mistakes you want to show us, why put them in puzzle format and have us guess which mistakes black might make?
This in no way helps us study endgames, other than learning that, if two beginners are playing, random moves will happen and might change the expected outcome of the game.
If this was the end of a game you played, post the details, and put it in the game showcase forum.