This one certainly works!
Hardest mate in 1 puzzles
@EvinSung:
1) Ne5#
2) Nc2#
(Highlight to see)
Once you look at all of the pins you may find the White-mates-Black answer in the post #305 puzzle.

@EvinSung:
1) Ne5#
2) Nc2#
(Highlight to see)
1) is selfcheck and therefore illegal.
Oh, yes, in that case: 1.Qd6#

2) One of bxc6 or fxe6 must be legal, I think that it is impossible to tell which of them though.
It actually is possible. One legal, and the other is illegal.
the answer is bxc6
Can you post the proof? I can't find it myself.
There are only 2 apparently legal last move for black: c7-c5 or e7-e5 (you want another one? please tell us). However, if Pe5 were on e7 on the last move, how did Bh6 travel from f8 to h6 during the game? Well, it can't and therefore c7-c5 is the only legal last move!
[COMMENT DELETED]