The speaker describes life in a basement apartment with the calm of someone chatting about an ordinary rough neighborhood, though the details quickly tip into the infernal. The rats are landlords, the commute happens on an exercise wheel, and the shower smells of sulphur (though the hot water is reliably quick). The title suggests the speaker is living beneath hell itself, and the upstairs "neighbors" are doing something loud and unsettling.
What makes the poem work is the gap between the horror and the tone. The speaker shrugs off the crushed-cigarette faces as probably "perfectly nice," guesses at parties or amusement parks to explain the shrieking, and even admires the rhythm of it all. This reads as a kind of weary coping, a refusal to panic. Yet the ending cracks that surface: when the noise stops, the silence is what wakes the speaker, who wonders "what fresh hell is this." The mood is darkly funny, but also uneasy, as if getting used to the unbearable is the real nightmare.