These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Alternative Character Interpretation: Sit down for a moment and think about this musical's take on Hyde. He still looks like Jekyll, just with loose hair and an evil grin. He brutally murders the people that pissed Jekyll off, and he rapes the woman Jekyll was attracted to but didn't dare become involved with because of the engagement to Emma, whom he later assaults at the wedding. For being a piece of romantic musical fluff, this show makes it easier than almost any other version of the story to interpret Hyde as simply a name Jekyll gives his repressed depravity. Congratulations, Frank Wildhorn, you have potentially beaten Alan freaking Moore at being Darker and Edgier.
That isn't an alternative interpretation, it's the canon one. In the source story, Jekyll straight up explains that that freedom is why he makes the potion, and it's why he continues to imbibe it. Even in the musical, Jekyll states that the potion makes him feel "twice as alive and tenfold more wicked, which intoxicates and delights me like wine." He's addicted to the freedom, and keeps up with it, not attempting to stop until his actions have gone well past the point of being unforgivable.
Am I a good man ... am I a mad man? There's such a fine line...
Creator's Pet: Lucy gets an unusual amount of songs despite being The Not-Love Interest in most revisions of the show, (she always has an unrequited infatuation with Henry, but it's rarely reciprocated in any production). The simplest explanation is that the character was written with Linda Eder in mind... who was dating (and later married!) writer/composer Frank Wildhorn at the time.
Indeed, most of Lucy's cut songs ended up on Eder's solo albums and cabaret tour after she left the Broadway Production.
Crowning Music of Awesome: Both Jekyll and Hyde get a ton of them, with "This is the Moment", "No One Must Ever Know/Confrontation" (in which Jekyll and Hyde duet), "I Need To Know", and "Alive" being the stand-outs.
Lucy does get a handful of really good numbers as well, though since her original actress was dating the writer it should be no surprise.
Evil Is Cool: Hyde represents everything Jekyll enters his experiments seeking to isolate and destroy, but his decision to use himself as the subject of the experiment proves a fatal error when this trope comes into play. Rather than being repulsed by Hyde's monstrous nature, Jekyll is initially fascinated by his darker side and envies his ability to act without morals or inhibition to enjoy life to the fullest. Unfortunately, Jekyll dramatically underestimates what Hyde is capable of with nothing holding his impulses in check while overestimating his ability to control him; once Hyde realizes suicide from the success-obsessed Jekyll is an empty threat, and that Henry is no longer strong enough to contain him even with altered drugs, he begins to rampage with impunity, alerting Jekyll to the danger he has placed himself and everyone he knows in only when it's far too late to regain control of the experiment.
Jerkass Has a Point: As with Strawman Has a Point below, we already have ample reason to dislike Simon by the time he voices his own objections to Jekyll's proposed experiment, but he has a point that Henry's well-intentioned goals don't change the fact his intended method of using personality-altering drugs on another human being in an attempt to remove evil from them is incredibly unethical from a medical standpoint. It can be argued that since Jekyll has the measure of what a jackass Simon is and the fact he brings this up more to humiliate Jekyll than anything else, Jekyll inadvertently ignores the realization his experiment really is impossible to condone because the people shooting him down are such jerks about it.
Romantic Plot Tumor: A huge percent of the songs and scenes in the musical are just the two love interests singing about being in love. They're good songs, but still. It takes about an hour into the musical for Hyde to even show up.
Strawman Has a Point: As Peter Filichia notes in his book Let's Put on a Musical!, the board members' unwillingness to sanction Jekyll's work is actually understandable. Although they're all portrayed as close-minded hypocrites, and if they had said yes he might have been able to better control the experiment, it's completely unethical to perform an experimental, possibly dangerous, treatment on an asylum patient (as he requested)—such a subject, among other things, would be unable to provide informed consent.
Tear Jerker: The song "A New Life" is pretty depressing enough as it is, much more so when you know what's about to happen afterwards.
In one production The Spider took the letter from her and called her a whore directly before the song (which began with her sobbing). Tears.
The very first song, "Lost in the darkness", qualifies, too, as Jekyll is visiting his catatonic father in the madhouse and promises him to find the cure, wishing him good-night in a tender voice in the end.
The Woobie: Say what you will about Linda Eder's clearly superior vocal performance, but the DVD Release features Colleen Sexton as Lucy and she sure looks like someone killed her puppy.
David Hasselhoff was the final Jekyll/Hyde in the show's Broadway run (the ads had him noting "This ain't no day at the beach"). One of the performances was videotaped and released on DVD. Some consider his performance to be Narm Charm of the purest kind, though it's clear that, skills aside, he certainly put his all into the role.
Takeshi Kaga was actually quite well-known for starring in musicals in Japan prior to his Iron Chef days — he had also played Jean Valjean and Jesus, among other roles.