It's a defining moment because Law maintains the same tone throughout the play. His is an adolescent Hamlet, a 1968 Hamlet, a never-trust-anybody-over 30 Hamlet. Also an 8,000-calorie Hamlet as Law leaps, prances, wriggles and elbows his way around the stage. In a narrow sense, there is nothing wrong with this. In fact everything that Law does on stage can find justification in the script. The trouble is that there is so much more. Hamlet is an adolescent, with a full repertoire of adolescent angularity. But he is also, as John Gielgud used to say, he is "a great Renaissance prince" (Gielgud said "ruh-NAY-sance," which turned the rhythm out nicely). Law's Hamlet is a catalog of missed opportunities.
By way of example, consider this non-exhaustive list: When Hamlet says "what a piece of work is a man," he speaks with awe and reverence; with the gravediggers, he is bantering and ironic; with his male friends, he is (at least some of the time) a model of masculine friendship; with his Ophelia and Gertrude he is jealous and obsessive; with Yorick, he gives us bittersweet nostalgia; with Horatio before the final conflict, he offers stoic acceptance. And so forth. It's why people who play Hamlet get to go into heaven by a separate door. Law doesn't have any of these except the adolescent part.
I don't suppose anybody gets them all (why Hamlet may work better in thee library than onstage. Branagh went a long way; he was old enough so he got the maturity, and artful enough to fake the youth (even Branagh had his limits (but then, Law is 36). I was never so nuts about Olivier but he did do some things right.
All this is a rotten shame, because so many things in this production work so well. Nearly everybody can mouth a classical line, which is no mean trick. The pace is right, the charcoal-brown setting is right. Polonius is a study in oily manipulation, and goes a long way to drive home the point that Denmark really is a prison: a nest of intrigue and betrayal. Gwilym Lee did an impressive job in what is thankless role as Laertes.
Geraldine James as Gertrude Gugu Mbatha-Raw as Ophelia brought a lot to the table, but each of them depends on what she can get out of Hamlet, and in any number of cases, it looked like they just didn't now how to respond to this young man living on emotional capital he hasn't earned. (Okay, gimme irony, Jude! Okay, now effusive! Okay....) When Ophelia says:
O, what a noble mind is here o'erthrown!...you do a quick systems check and tell yourself: no, not tonight.
The courtier's, soldier's, scholar's, eye, tongue, sword;
The expectancy and rose of the fair state,
The glass of fashion and the mold of form,
The observed of all observers, quite, quite down!
Afterthought: I admit I set a high standard here. Fact is, the one character I'd really like to see play Hamlet just doesn't seem to be on offer. That would be Michelangelo's David in the Accadamia in Florence. Now, there is a Ruh-nay-sance prince.
Afterthought II: My friend Lily reminds me of the classic Dorothy Parker review: he ran the gamut of emotion from A to B.