1.f5? zz 

1...Kc3 2.Bc1 Kd3 3.Bb2 Kd2 4.Qe2#, 3...Kc4 4.Qb5#; 2...Kc4 3.Bb2 Kb4 4.Qb5#, 3...Kd3 4.Qe2#; 2...Kb4 3.Bb2 ~ 4.Qb5#, but 1...Kc4!

1.Qc5! zz 

1...Ke3 2.Qc3+ Ke4 3.Bf6 K*f4 4.Qf3#, 3...Kd5 4.Qc6#; 2...Kf2 3.Qf3+ Ke1 4.Qe2#; 1...Ke4 2.Qc3 Kd5 3.Bf6 Ke4 4.Qf3#, 3...Kd6 4.Qc6#; 

1...Kd2 2.Qc2+ Ke3 3.Sf5+ Kf3 4.Qg2#