First of all, I think the ending was just what it needed to be, but I definitely don’t think that it is the end of the story because I believe the story was set up for good to (at least) temporarily prevail. Instead, no one won.

I wouldn’t rule out a return of Penny in some form or another. Many people have said that “Mutant Enemy” is serious about deaths, but that doesn’t meant that there has never been times where characters who have died have come back. Buffy died a lot and kept coming back (although, notably, not without repercussions). There are also two mentions of messing with time in this world (Hourglass and the freeze ray). Finally, this musical is based in a comic book world, and in comic book worlds people rarely stay dead forever.

Now, to my main point:

I’m really surprised that no one has started discussing possible foreshadowing from these lyrics from “A Perfect Day (So They Say)”:

“There’s no happy ending / so they say”

Think about it: in a song where everything that “they say” is incorrect or altered beyond truth, Billy and Penny sing that “there’s no happy ending / so they say.” It might just be foreshadowing the unhappy ending of this show, but that doesn’t get at the other layer of this song, which is all about misinformation and lies. I wouldn’t be surprised if this comment is a nod to the reaction that the creators expect from the fans of Dr. Horrible…a little bit of cheekiness about knowing something we don’t.