1.Kd4? threat: 2.Kd3 zz. Kf4  3.Sh2(e5) zz. Kg3  4.Sf3 zz. Kf4  5.Be5# 

4...Kf2  5.Bh4# 

but 1...Kf4!

1.Bh8? zugzwang.

but 1...Kh4!

1.Bg7! zugzwang.

1...Kh4  2.Kf4 zz. Kh5  3.Se5 zz. Kh4  4.Sf5+ Kh5  5.g4#

each white piece makes only one move