Baltimore’s Meyerhoff Hall was not very full for Thursday night’s performance by Marin Alsop and the Baltimore Symphony Orchestra. An abridged version of highlights from Wagner’s “Ring” turns out to be a hard sell. But you may have to hear it to understand why. It’s not unlike listening to excerpts of film scores, evoking the action of a dramatic work you know well — except that people who know Wagner well tend to want to hear it in the original form, like the act of “Die Walkure” that Alsop and the orchestra played in February.

And people who don’t know Wagner are not likely to want to buy tickets to sit through an hour of it — not least because they won’t know what the heck is going on. Yes, there were supertitles over the stage, but they were vague at best and possibly confusing: You could learn from them that Brunnhilde sacrifices herself to save the world, but newcomers might be more interested to read that she rides her horse into her beloved’s funeral pyre while the gods go up in flames in the distance.

Percussionist Colin Currie brought slyness to his role in “Der gerettete Alberich.” (Marco Borggreve)

That the experience — a grouping of greatest hits, arranged into a single piece by Henk de Vlieger — felt like Wagner Lite is also unfair to both Alsop and the orchestra, who did some heavy lifting in some significant music. Alsop brought out none of the implicit mystery in the opening chords of the “Rheingold” prelude, when the music swirls up out of the deep and finally floods into a sunlit riverbed; here, they sounded heavy and routine, and generally too loud too fast. But they built to a lot of tension at other moments: Siegfried’s death, or the climax of the funeral march, or even the finale, which is the most film-score-like and arguably primitive section of the whole piece, as one leitmotif after another gives, in effect, cartoon instructions to the stage director: “Now fire! Now flood! Now Valhalla burning! Now redemption!” All of that, of course, was left to the imagination — and entirely closed to those who didn’t already know the leitmotifs in question.

It was a nice idea for a program; Alsop paired the Wagner with Christoph Rouse’s percussion concerto “Der gerettete Alberich,” which deals with what happens to Wagner’s evil dwarf — the one who steals the gold and makes the Ring in the first place — after everything else goes up in smoke. It, like the “Ring” arrangement, is organized around a narrative rather than an abstract musical structure, and the percussionist Colin Currie slyly intimated the figure he was playing, without overdoing it, as Alberich slunk away in a creaking of woodblocks and worked through a veritable thicket of instruments, exploring his options. It was perhaps slightly more sophisticated than the “Ring” excerpts, and certainly had more inherent vitality — only emphasized by the encore, given by a group of young students from the orchestra’s OrchKids program, who came out and energetically pounded on plastic tubs with a truly welcome vigor.