Showtime has renewed “Penny Dreadful” for a third season, which, after Sunday’s finale, provokes some mixed feelings. That’s not because the show isn’t great fun to watch, but rather because there was enough poetry in its final chapter that even with numerous loose ends, it frankly wouldn’t have been a bad place to end things. As it was, the season-long story line involving a Satan-worshipping coven paid off handsomely, before scattering members of the central cast in a manner that will require dexterity to reconstitute them. Fortunately, series creator John Logan appears up to the task.

As rich as the season was, it often didn’t seem to be going anywhere with any urgency, with Logan and his splendid cast luxuriating in the florid dialogue and Gothic atmosphere. So it came as something of relief to see the pace quicken and tension rise in the final two episodes, which forced western gunslinger/part-time werewolf Ethan Chandler (Josh Hartnett) and the coven’s psychic prey, Vanessa (Eva Green), to grapple with both their burgeoning romance and individual curses and/or gifts.

That included, in one of the more show-stopping sequences (and SPOILER ALERT if you’re not caught up), the two’s brutal battle against one of Ethan’s past victims, in a desperate two-on-one fight that brought to mind Alfred Hitchcock’s “Torn Curtain.” The finale culminated in a full-out assault to rescue Sir Malcolm (Timothy Dalton), who the witches’ leader (Helen McCrory, a terrific addition this season) was using as bait to lure Vanessa into her lair.

Still, “Penny Dreadful” is often more about moments than plot, and that was especially true of the finale. Logan has deftly woven small elements of mythology into his narrative, such as the revelation that Ethan’s real name is Ethan Lawrence Talbot – “Lawrence Talbot” being the tortured lycanthrope played by Lon Chaney Jr. in the 1941 monster classic “The Wolfman.”

Ditto for the fascinating romance between Dorian Gray (Reeve Carney) and Dr. Frankenstein’s latest creation (Billie Piper), drawn to each other based on their respective immortality, based as much on narcissism, it seems, as anything else. Piper’s dismissal of the good doctor (Harry Treadaway) was both a lovely bit of writing and positively chilling, made all the more poignant by the cruelty inflicted on the Creature (Rory Kinnear) before he turned the tables on his captors.

After uneven patches during the first season, Logan has made these characters his own, abetted immeasurably by the sumptuous trappings and high-quality actors spouting those lines, even if they’re unlikely to receive commensurate awards consideration or prestige because of the subject matter and genre.

That’s not to say “Penny Dreadful” is without flaws. The witches, for example, proved too easy to overcome, the psychological warfare waged against Malcolm dragged on a bit too long, and Hartnett’s makeup has consistently looked more like a grownup Eddie Munster than a fully formed werewolf, especially for those weaned on “An American Werewolf in London” and “The Howling.”

Those observations amount to quibbles, however, given the show’s sensuous pleasures – or how favorably it compares with the movie version of “The League of Extraordinary Gentlemen,” which explored similar terrain.

As noted, the third season will face sizable hurdles at the outset, due in part to the way season two dispatched key players on boat voyages to three different continents. Still, as has been demonstrated by the clever way these mythical monsters have bumped into each other, in “Penny Dreadful,” it really is a small world after all.