this one is easy
All which I had to say about these puzzles is already written in the title.
i totally agree with u, oinquarki
1st puzzle has two solutions, not a big problem but it is slightly dissatisfying to make a winning move and see the app say that you are wrong. You could solve it by putting a white piece on one of the spots.
2nd puzzle is great, just too bad that you didn't get the winning move yourself, in the displayed variant white can avoid mate by 2. ... Kh6. It's not one you picked from somewhere else without getting along the correct solution, is it? 'Cause it's marvelously well constructed for a puzzle that the creator didn't get right himself.
3rd puzzle, my 'puter says it's a black win, not surprising as queen versus rook is by the book a won position.