Well first of all, it shows how very much we miss from having so much Troughton on audio only, he's such a visual actor that even the best recons can't really convey the subtle (and sometimes not so subtle but still hugely entertaining) nuances he puts in that elevate even the most ordinary and dull lines. He almost single handed drags this story up by the boot straps and raises it up above a slightly silly and done to death premise (I'm actually surprised no one involved remembered they'd done the evil double of the Doctor thing only two years earlier, sure different production team but they apparently had a list of done stories on the wall of the production office specifically to avoid this sort of thing).
Hines is as solid as ever, but doesn't really get a lot to do. I'm not a huge Victoria fan, but I do have a completely random thing for women in tartan skirts (Jamie obviously leaves me very confused) so she at least looks very nice.
The direction was probably Letts best for the show, I think not being the producer and thus not having free reign to do whatever he likes coupled with not being able to carry out his strange obsession with CSO (I think even George Lucas at his worst would baulk at using greenscreen to do an ordinary living room as happens in Terror of the Autons) in black and white helped there.
Though we do get the monochrome equiverlent in a back projected garden (and even though the trick used is quite smart- when Jamie's walking towards them in the distance he's on the back projection before a couple of cuts let him sneak into the set, creating the sense of depth) it does feel like a slight waste of location filming when they could have just had a set with a bush.
Overall though, a nice fun and surprisingly pacey story. The confrontation at the end, however brief, is well done as well. IIRC I once read claims that the one shot of Troughton looking at Troughton was done by superimposing a picture of the still Doctor over the scene after the spit-screen had failed, but no, he's clearly moving and the fact the split is done at an angle makes it feel nice and different from the usual ITC stuff.
It does make me smile though that Salamander's accent is exactly the same one Troughton uses in shows like Danger Man and The Saint whenever he's playing a swarthy foreigner of any nationality.
And that scene of him casually smoking his giant cigar, very proto-Delgardo isn't it?
The sheer, delightful, silliness of the opening beach scene really makes me want to see the very similar one that opens Fury From the Deep now.