The plot synopsizes from IMDb:
"An aspiring supervillain must balance his career and his pursuit of a beautiful do-gooder."
"A nerdish florist finds his chance for success and romance with the help of a giant man-eating plant who demands to be fed."
But, as I watched Little Shop of Horrors yesterday, all of the little similarities struck me. Before I go on, this is just a fun exercise - both shows are amazing and worth watching more than once :-)
Our Cast of Characters (both of these shows cast actors who were not known for their singing rather than Broadway stars)
Dr. Horrible Little Shop of Horrors
Billy / Dr. Horrible Seymore
Captain Hammer Orin (Dentist)
The Evil League of Evil The Plant from Outer Space
The Fans The Greek Chorus
The storyline in Little Shop starts before Dr. Horrible, as we see our hero meet and grow attached to what will soon be controlling them (the plant and the league).
Both of our heroes are madly in love with a girl that they work with / see at the laundromat. But, they cannot just tell them how they feel - or even talk to her, in Dr. Horrible's case.
Both girls have had a tough life, and are going out with a guy who doesn't love them, or even really like them, and is just using/abusing them.
Both boyfriends are in a position of power (hero/dentist), and love to control others. After seeing the two together, Billy and Seymore sing about how the world seems so wrong, and is falling apart.
"Listen close to everybody's heart
And hear that breaking sou - nd.
Hopes and dreams are shattering apart
And crashing to the ground.
I cannot believe my eyes
How the world's filled with filth and lies!"
She deserves a prince, not a sadistic creep like him.
The man's a total disgrace to the dental profession.
l don't know what's going on, sometimes. Seems like the whole world's going crazy.
Moving on with the plot ... The hero keeps doing what the plant/league asks in an effort to get the girl - that's their real goal. Neither of them realize that they could get her on their own, because the girl likes them as well.
One key difference here is the consequences of following the plant's/league's orders: Seymore gets what he wanted (plus some), where Billy loses everything ...
Things come to a head, and the plant/league asks for a life. Billy and Seymore both are shocked, and refuse - but are convinced after seeing their love and her awful boyfriend together, and resolve to kill him.
They come to the boyfriend with a Gun, almost shoot him, and then the boyfriend accidentally kills himself / sends him crying for his mama. Either way, he is off the scene. For a few moments, Dr. Horrible thinks he has everything he wanted ...
After feeding the plant a couple bodies, Seymore realizes he can leave, but just as he is about to have everything he ever wanted ...
Penny is dead, and Audrey is eaten by the plant.
Now in the movie-musical, the hero saves the girl, and they live happily ever after. But in the original movie, and the theater version of the musical, both the hero and the girl are eaten by the plant, who then takes over the world.
This is a great article detailing why this was an unfortunate change, as it erases the moral message of the show (murder is bad, and has consequences).