I read an interesting little series called Gamma. It only clocks in at 20 chapters from start to finish, and it tells a coherent story in that time.
It is set in a world where an alien invasion bathed the world in the mysterious Lambda Energy, which causes some humans to develop superpowers and some animal to transform into Kaiju-like beasts. But Lambda Energy is a fickle thing, and most supers only enjoy a five year career before their powers burn out entirely. Some only make it one year. Not all powers are created equal either, with some supers being world-class and some being barely super at all. This leads to a lot of complex feelings, and that's where our heroines, professional counselors in the Earth Defense Force, come in. They're super-shrinks.
It's an interesting worm's eye view of a superheroing world, and I was surprised at the conclusion the heroes reach in the finale:
Is it a great manga? No, not at all. It moves away from the super-shrink idea and becomes a bit more straightforward as a shounen adventure in the final arc.
There is also way too much emphasis on underage bodies and an eye-rolling running joke that the main character's older sister is a giant siscon. It's even more unsettling when characters highlight the fact that a young character has had her growth stunted, making her look even younger. That shit is gross.
But it's a neat little meditation on altruism, the price of power, superhero hangups, and how the common people get by in a world of supers. It's only 20 chapters. You could knock it out in an afternoon.