Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Dark, Opinionated
This play is definitely dark. We're got a brutal murder, the corpse of dead bird, and the first stage direction tells us we're in "gloomy kitchen" of a "now abandoned farmhouse" (1). From the first moment they see the stage, the audience is going to know they aren't in for a light comedy.
It's also totally clear that the author of this play has some strong opinions about the treatment of women. Check out this set of lines:
COUNTY ATTORNEY: No—it's not cheerful. I shouldn't say she had the homemaking instinct.
MRS. HALE: Well, I don't know as Wright had, either. (43-44)
Here, Glaspell shows how sexist men are by assuming that women can only be worth anything if they're good homemakers. Next, she cuts that idea apart by jabbing us with the idea that it's also men's responsibility to make a home. As a writer, she's not being all that subtle with her opinions. But given the massive amount of oppression that women dealt with in her time, it probably just wasn't the time for subtlety.