Hamlet enters the stage earlier than usual in Oskar Eustis’s chock-a-block Shakespeare in the Park mounting. Clutching a beat-up valise and a single red rose, Michael Stuhlbarg’s haunted prince sits in front of his father’s grave and crumples, nearly paralyzed by grief. He remains in this position as the play’s first scene — one of the few that does not require his presence — commences directly above him, atop David Korins’s stone-and-metal set.

Enjoy this bit of repose, Mr. Stuhlbarg. If this too solid flesh were to melt, it would likely be through sheer exertion. Mr. Eustis, in only his second Public Theater appearance as director since assuming its leadership in 2005, is making up for lost time. Massive puppets, militaristic flourishes, trick endings, a leading man who appears to be essaying the greatest role in Western literature from atop a pogo stick: This fidgety production has more concepts per scene than the idea-glutted works of Tony Kushner and Paula Vogel, two of the many contemporary playwrights Mr. Eustis has championed. Many of these gambits are intriguing, even ingenious; nearly as many are trite or unsupported. Mr. Eustis’s résumé includes several years as a dramaturge, a somewhat nebulous behind-the-scenes job within the theater world that typically includes providing playwrights and directors with sheaves of information and suggestions. Without a more judicious director (or, obviously, a bristly playwright) on hand to apply the brakes, the flood of dramaturgical notions on display threatens to engulf this “Hamlet.”

Which is not to say this prince is going down quietly. Mr. Stuhlbarg, who has excavated pulse-quickening veins of emotion in emotionally constricted saints (“The Voysey Inheritance”) as well as sinners (“The Pillowman”), embraces his inner showman with jarring fervor. His Hamlet stomps his feet in grief, impatience, anger, and glee; the final sword fight with Laertes (David Harbour) may be on the tepid side, but Mr. Stuhlbarg more than compensates with a battery of prances and hops between thrusts. His is easily the busiest Hamlet I have seen, and the method in Mr. Stuhlbarg’s madness can be a bit too methodical.

But while the specifics frequently grate, this approach is not without merit within the context of Mr. Eustis’s staging. Upon returning to Denmark, this Hamlet is inconsolably morose; when he confides to Horatio early on that “I do not set my life at a pin’s fee,” it sounds more than ever like a depressive’s cry for intervention. This plea, of course, is answered from beyond the grave, when the ghost of his father (a chilling Jay O. Sanders, in the first of three splendid roles) commands Hamlet to avenge his death by slaying his brother, the usurping Claudius (Andre Braugher). Hamlet vows to remember the ghost “while memory holds a seat / In this distracted globe,” and the command to kill does away with all distractions. The pendulum swings, and as with many depressives, a sort of task-oriented mania settles in. The timeless question of just how premeditated Hamlet’s madness is remains tantalizingly, rewardingly unanswered.

As so often happens with Shakespeare in the Park, though, this central theme is crowded off the stage by a grab bag of supporting performances. (The scattered quality extends to Ann Hould-Ward’s costumes, an awkward hodgepodge of periods and styles.) Margaret Colin’s tightly coiffed, first lady-esque take on Gertrude leaves her with little to do, and Mr. Braugher’s Claudius relies too heavily on officious bluster. But Mr. Sanders executes a near-perfect hat trick, following up his Ghost with an irresistibly hammy Player King, who somehow holds his own alongside Basil Twist’s stunning marionettes, and a winningly naturalistic Gravedigger. Sam Waterston, who himself played Hamlet in Central Park in 1975, has settled into the windbaggy dotage of Polonius with almost disconcerting ease; when Polonius fumbles for his thoughts in Act II (“What was I about to say? / By the mass, I was about to say something!”), audience members could be forgiven for thinking that the canny Mr. Waterston himself had drifted.

And until she is overwhelmed by an all but unplayable punk-chick mad scene, Lauren Ambrose charts the decline of Ophelia with devastating subtlety. Her mildly flattered bemusement at Laertes’s condescending tenderness gradually gives way to tight-lipped anger at her powerlessness within the court, followed by clinging incomprehension at Hamlet’s subsequent cruelty. “O, what a noble mind is here o’erthrown,” she says of Hamlet’s scattered state, but Ms. Ambrose’s marvelous control makes Ophelia’s fate the sadder and more cruel toppling of nobility.

Mr. Eustis has replaced the clutch of flowers that Ophelia dispenses in her final scene with small rocks stuffed in her pockets — a poignant touch that both illustrates her madness and foreshadows her imminent death by drowning. This “Hamlet” teems with similar flourishes, culminating in the climactic appearance of Fortinbras (Piter Marek). The first impulse is to marvel at the chutzpah in crafting a truly surprising denouement; this blinking admiration is replaced almost immediately by the realization that it is in direct and complete contradiction to the dialogue that comes immediately beforehand. Like too many of Mr. Eustis’s whirling innovations, it is unexpected because it is unearned. Until June 29 (Central Park, enter at West 81st Street, 212-539-8750).