Fascinating but frustrating. Those are the two words that most readily come to mind when describing David Grimm’s Kit Marlowe, Rorschach Theater’s latest production. The work’s plot is undeniably gripping, but the play is frequently hindered by a number of performances that, while certainly not poor, are strangely uneven.

What results is too many moments where a scene builds in momentum and tension, but is ultimately derailed by a flat or off-beat line delivery. Some actors seem miscast; others just seem off their game at times. William Aitken as Sir Walter Raleigh seems an example as a former. Aitken is great in a few of Marlowe’s moments, namely when he’s showing the explorer’s vulnerable, lovesick side. But otherwise, he never seems the imposing, romantic figure we’re told Raleigh is. Reece Thornbery is charmingly hammy as the famous actor Edward Alleyn, but unfortunately the hamminess carries over into his interpretation of the scheming Anthony Babington, whose villainy is so over the top that he’s literally hissing. Matt Dunphy’s first few moments onstage are a little wince-worthy — his prissy, uptight Thomas Walsingham, Marlowe’s friend and lover, doesn’t feel natural — but perhaps Dunphy just needed some time to relax, because he ultimately settles into what becomes one of the work’s most sympathetic characters.

Luckily, our titular character is required to do most of the play’s heavy lifting, and Adam Jonas Segaller is more than up to the challenge. Kit Marlowe focuses less on the figure’s status as an author and Shakespearean rival, and more on the legend that he was actually a spy for the crown of England. Segaller’s Marlowe is a larger-than-life figure whose early moments onstage convey an outsized joy for life and thirst for adventure — even as Marlowe descends into treachery and deception, it takes a long time for circumstance and tragedy to break through that untouchable exterior. Segaller is no less convincing, however, when Marlowe’s sins catch up to him in the second act.

He also is the most masterful in the group at selling Grimm’s many flowery soliloquies, which invoke the style and poetry of Marlowe’s writing. Also excellent is John Brennan as the evil Sir Francis Walsingham, who gets Marlowe embroiled in the world of spying and secrecy (though director Jessie R. Gallogly’s decision to have his booming voice occasionally echo spookily from afar in Marlowe’s brain is a little heavy-handed).

Grimm is working with meaty material here, and the twisting, delving plot is one of Kit Marlowe’s greatest strengths. We’re immediately embroiled in the intrigue of Marlowe’s underground world, and the work has plenty of swashbuckling action, horrifying torture, and yes, unapologetic male nudity, to hold our attention, even when it’s running a little long. Grimm smartly sets up Marlowe to be an embodiment of many of his famous characters, from Faust to Tamburlaine, and the story has some credible surprises up its sleeve to boot. Its language can be overwrought at moments, and Grimm can hammer home the same on-the-nose character revelations too frequently. But it’s more often appropriately atmospheric when handled well, and has moments of lighthearted wittiness, such as a Raleigh rival scoffing at the figure’s presentation of a “topato” rather than a potato from the Americas.

Rorschach’s spare wooden sets conjures the time period while leaving plenty to the imagination. One crucial scene, though, has Raleigh taking Marlowe out on an (imaginary) boat for a crucial revelation — the moment is a powerful one, but Gallogly’s staging definitely seems to indicate that Marlowe literally walked on water to escape Raleigh in disgust. It’s a scene symbolic of this production — a climatic and moving emotional exchange thrown momentarily off balance by a clumsy misstep.

Kit Marlowe runs through Dec. 2 at the Santuary Theatre in Columbia Heights. Tickets are available online.