So let's take a look at the spectrum of poems here and talk about tone ...
"April Showers" -- A super baby shower. All my fluffy fluffness, let me show you it! These "slice of life" poems serve multiple purposes: they show how superpowers affect every aspect of life, they develop characters with a life outside of crimefighting, and they provide an emotional comfort zone between the more intense episodes.
"Singing in the Rain" -- Soups and other folks at karaoke night. Revelation. I often write poems that go around a set of something, revealing a new tidbit with each aspect. In this case, the songs chosen will tell you things about the people who sing them. There are light and dark tones woven together, but also personal things which are not just fluff but mark important parts of the storyline.
"SPOON in Every Pot" -- Social activism about superpowers. Problem-solving. Some poems are really all about a particular issue and how the characters work through it. These can be more or less intense emotionally.
"The Ones Who Would Do Anything" -- A homeless teenager takes other homeless children under his protection. Hurt/comfort. I write a lot of this, because it lets me ramp up the intensity by racheting between hard and soft elements within the same piece. It's easier to deal with difficult issues when there are soothing aspects alongside them. I also really like tackling these complex topics that can't be solved with a wave of authorial hand, but require real problem-solving effort. These plotty poems make up a predominant amount of most storylines that I write.
"Enter the Dark Horse" -- A team of superheroes hit a made science lab, and wind up doing more harm than good. Ambiguous morality. Sometimes, who is the hero and who is the villain is a matter of perspective. In fact, my partner Doug said that he thought they were a team of supervillains, until he finished reading the poem and the notes. Now that I've got a solid foundation laid down so that people know what the setting is like, I can go into the grey areas and raise questions like, "What does it mean to be a supervillain? What does it mean to be a superhero? How can you tell the difference?" Because it's not always a clear-cut division.
"A Perspective, Not the Truth" -- Spying on a girl with nascent superpowers ends in tragedy. Slippery slope. Brad is a character I developed to fill a gap, when I realized that I had several supervillains who were shifting slowly toward the good side, but nobody going the opposite way which is actually the easier direction. So I hunted around to find someone who thinks of himself as a hero, yet keeps making the kind of moral compromises that move him inexorably in the wrong direction. This is dark, creepy, uncomfortable stuff because everyone faces moral decisions and you have to make the decision each time whether you will do what is right, or what is easier and more beneficial to your self-interest.
"The Taste of Rust" -- A supervillain realizes new limitations, and reacts badly. Some people are just plain set in their ways. Wicked introspection, all hurt no comfort. This is a poem I wrote because someone wanted to know what happened to the bad guy after a fight. It's the kind of story that mainstream comics just don't tell, so of course that fascinated me. Well, for every guy who gets hit over the head with a cluehammer and decides to fix his life, there are more who refuse. Antimatter changed course; Shiv chose not to. The inside of Shiv's head is a pretty awful place. The fact that he exists, and you get to see how he thinks and feels about events, provides a contrast to other characters like Stan (who is fundamentally a good person) and Lawrence (who tried on wickedness and decided that he didn't like it). This functions as a kind of 'stopper' where you can see a very similar impetus having strong motile power for one character but coming up short for another.
"The Bones of Truth" -- Not a battle, but the aftermath and analysis of one. Witness fic. The worst has already happened, so the heroes can't prevent it or fix it. All they can do is figure out what happened and pay their respects to the dead. This poem deals in scary aspects of technology, but also the finality of death. It's primarily about recognizing the fallen, though; some stories aren't about triumph but about standing witness to what has passed.
Now look at some of these in batches ...
"April Showers" and "Singing in the Rain" fall toward the lighter end. They show that not everything meaningful is necessarily a battle or related to world issues. Lighthearted things bring comfort and keep people going. "SPOON in Every Pot" and "The Ones Who Would Do Anything" are different kinds of plotfic. The focus is on what happens, how people deal with challenges. So the tone can vary in those. "Enter the Dark Horse" and "A Perspective, Not the Truth" fall into the middle range between good and evil. They're uncomfortable; they raise questions. "The Taste of Rust" and "The Bones of Truth" are aftermath stories. They mark a fundamental difference between Polychrome Heroics and most superhero literature, by paying attention not to the peak of action but to how it affects people's lives in the long run.
"Singing in the Rain" and "The Taste of Rust" are different kinds of characterization. They look at who these people are and why they act as they do, which sheds light on their behavior in other installments. "SPOON in Every Pot" and "The Taste of Rust" show that superheroes don't always have to kill, and can still have a real impact. In mainstream comics, people throw each other around a lot without necessarily thinking about the results. I like to show both sides -- where some of the fights are nerfed, or one character can put down another without having to do lasting harm; but also, where it's possible for someone to sustain permanent injury without that even being the goal. There's a spectrum of force, and varying results. On the whole, though, Terramagne isn't a setting littered with corpses. So when we get to the few poems that DO include death, such as "Enter the Dark Horse," "A Perspective, Not the Truth," and "The Bones of Truth" then it has more impact precisely because it is rare. These conflicts have real consequences, and sometimes those are fatal. But look at "Enter the Dark Horse" in particular, and you can see an argument why that level of violence is inadvisable: it tends to mint supervillains. That's not an accident; a disadvantaged background correlates strongly with criminal activity.
Consider the implications and your own tastes ...
What works and doesn't work, and why? What do you like or dislike? What things make you want to read a poem, or skip it? How dark is "too" dark for you? How light is "too" light? Where does the plausibility threshold lie? What kinds of grit do you want to see, because maintream comics ignore some really obvious implications that are important? What have you seen too much of, and you're done with it now, you want something else? How do you like to see difficult topics handled? How do you feel about the proportion of light to dark? How important is tone to your enjoyment of an individual installment or a series as a whole? Does it make a difference in crowdfunding, where YOU can influence what happens by prompting, commenting, or donating? What else do you think of when contemplating tone, especially laid out in a range like this?