In a way, I think it's actually closer to the less known (and older than Watchmen) original Squadron Supreme mini-series, even if it's just coincidence and the writer likely has never heard about that series. In that mini-series, we got Marvel's take on DC's various characters and their attempt at improving their world, after a crisis that led to people looking at super humans with suspicion, only to lead to unintended consequences and a division breaking between them.
The characters in Concrete Revolutio, although having twists, are generally still fairly close to the source material being homaged, with many different origins and powers, while Watchmen attempted to homogenize everything and ground the setting, by making it so no one had real powers aside from Dr.Manhattan, who was the singular miracle (well, aside from the random people with psychic powers). Concrete Revolutio isn't trying to ground and portray the characters themselves as realistic, even if they inhabit a gray world. I think the anime-ish designs actually play well into that aspect too.
On the other hand, the Watchmen comparison does work with the actual core storytelling, the non-linear narrative, and also the alternate history aspect, which add an extra dimension to the series' events. After the first couple of episodes those elements have integrated well into the storytelling too and added to the show, even before the pay off with the main story.
