It was very atmospheric, I'll give it that. Every land shot is in the dark, with fog. I enjoyed the accents. Especially Admiral Nelson's. (And Crane looked like he enjoyed it, too.)
The whole plotline, however, left way too many questions.
Apparently the mere mention of Nessie is enough to dry up any sense of logic, even with men who live in the area and presumably are familiar with the legend. MacDougall announced to the men at the pub that he and the others were in their launch on the loch when they were attacked--yet he and the dead Carruthers were bone dry. Also, no one seemed to take note that this supposedly living creature had a light flashing at regular intervals in its throat.
Neither Nelson nor Crane think to ask MacDougall for proof of idendity.
Given what we learn later in the episode, the poacher's second attack on Nelson makes no sense. Neither does Lester's failure to announce that he just saved Nelson's life.
Crane indicates that he thinks that the stories of Nessie are circulated to encourage tourism. MacDougall responds by asking if Crane can think of a more remote, lonely place for tourists. This is a rather ironic statement today, given the millions in revenue generated by Nessie every year.
An underwater passage to the loch that can be navigated by a large submarine is a momentous discovery in itself--and could be used to explain just how Nessie (and others, perhaps) reached the loch in the first place. Yet no one really seems to care.
Lester informs Nelson that he has questioned the poacher who attempted to kill Nelson, and has learned everything about why--and how--the science team were killed. When "Nessie" approaches to ram his boat, Lester may have been frightened at the emminent peril, but he should not have panicked and started screaming, "The Monster!"
A rather sizeable package of explosive was placed inside the workings of the torpedo launch. I found it hard to believe that they could not see any signs of possible sabotage. By the way, it appears that Kowalski, in addition to his many other talents, is also a trained electrician--Crane ordered the "duty electrician" to report, and 'Ski was first on the scene.
We've seen ample evidence of how sensitive the Seaview's scanning equipment is--yet they could not determine that "Nessie" was just another submarine until they saw it with the naked eye.
Nelson was ordered to use a mini-sub to bring MacDougall and the papers over to the Nessie sub--in three minutes. Three minutes to collect the papers, get down to the Missile Room, get suited up, and launch a sub. They had previously given them six minutes to accomplish all this, which would have been remarkable enough. Three minutes is ridiculous.
Having discovered that MacDougall was not on board the mini-sub, the Nessie commander never thought to ask, "Then who is on board?" It was also very obliging of them to hold their fire for thirty seconds without asking why.
I did like how they left open the possibility that something unknown might still be in the loch.