What we have here is an example of a cyclic Zagoruiko. In both the try- and
post-key phases, Black has two defences x and y. In one phase, they are refuted
respectively by mates A and B, in the next, by mates B and C, and in the third by
mates C and A.
Thus, after the first try 1.Qxd3? (threat 2.Qf3) the thematic defences 1...Sxe5 (X)
and 1...Sxd4 (Y) are met by the mates 2.Sc7# (A) and 2.Bxb7# (B), but the third
defence 1...Ra3! refutes.
A second try is 1.Qf5? (with the same threat). Now 1...Sxe5/1...Sxd4 run into the
mates 2.Bxb7(B) and 2.Sb6 (C), but 1...g4! refutes.
Finally, after the key 1.Bf8! Threat 2.Qh1, we have 1...Sxe5 2.Sb6# (C)
and 1...Sxd4 2.Sc7# (A)
So what we have is a 3x2 Zagoruiko (two changed mates in three phases of play),
with a cyclic pattern across the three phases, which can be summarised as
1. x-A y-B / 2.x-B y-C / 3.x-C y-A.