Could've used Patrick Stewart, too. There is mention of terraforming Mars, which places it somewhere between the 22nd and 26th centuries, but then he talks about the future of Peledon making it at least 3985. There is, however, something about the Doctor buying action figures that I can't resist. Other than that, this short prequel to Original Sin just explains why UNIT HQ was different in The Three Doctor. I think they just had a bigger budget.
CHaracterization is dead on though.
My personal favorite of the bunch. Shakespeare and the Doctor go together really well. He has the Ainley version down. Instead of concentrating on conquering the universe or something, the Master is obsessed with killing the Doctor. Only spotted on in-joke, I must be slipping.