1) How are you generating these puzzles? If you are committed to them being low-quality, how are you handling duplicate solutions? Why is it possible for the king to be generated in check, but not for capturing the king to be the solution?
2) What's up with gold?
3) The game seems to crash when loading the first non-combat encounter, at least the two times I tried
4) A higher difficulty seems to result in less time to look at the puzzles, but have no effect on the difficulty of the puzzles generated.
5) Are all the puzzles just mate in one? It's pretty rare to find a mate in one puzzle that isn't immediately obvious-- most of the time they rely on some trick, e.g. you need to force black to mate you, it involves en passant, etc. Besides these 'gotcha' questions, mate in 1 puzzles can't be terribly difficult from a chess perspective, so your game will be deriving its difficulty from the time pressure coming up against things like lag and input device speed, which is usually pretty frustrating.
If I were to make a suggestion, it would be to pull the positions from real games and to give higher difficulties exponentially longer amounts of time to think, but linearly increasing puzzle depth. So if easy gets mate in 1 and 20 seconds, medium gets mate in 2 and 40 seconds, hard mate in 3 and 80 seconds, very hard mate in 4 in 160 seconds.