This is Gaiman storytelling and featuring themes which feature elsewhere in his work, such as a mysterious and magical spear (which featured again in Neverwhere), archetypes, including the warrior, soldier and hunter (the female warrior-hunter character featured again in Neverwhere too) and characters developing or out-growing the identity they begin the story with (like in Neverwhere), this not necessarily being a move from the inferior to the superior but rather a transformation, becoming something different.
It is a story from within the Spawn universe, the character of Spawn and his sembiotic "living" costume imbued with defences and powers is present, the back story of which is nicely presented in synopsis within the caption boxes but it is really a tale of heaven and the angels, rather than the devils and Hellspawn. The angels are all paragons of the female form, scantily clad, physically mighty and striking a pose in almost every page. However, its all tastefully done and to a certain extent I suspected was treating this all with good humour and probably a wry sense of its likely audience of comic reading adolescent males.
The main protagonist is Angela, an angelic opponent of Spawn, who has been set up in an internal power struggle within the heavenly power structure, Spawn is involved by well meaning but bungling friends to try and exhonourate Angela of blame, there is a very action packed (but also corny romantic) interlude when the two opponents are thrown together in such a way as to make alliance the best idea and finally the plot against Angela is explained, she makes a choice then as to what she will do from there and decides on something anomalous in the Spawn universe.
The freelance neither there-nor here conclusions probably feature a lot of the cultural background of the time this was originally published, when binary opposites were considered old fashioned, fusion and cross overs or constant drive for novelty, originality, choice where en vogue. It also in some ways reflects the history of Spawn as a phenomenon too, when the artists and writers, essentially the creators, were aiming to come up with something new, not Marvel, nor DC but which still managed to resemble each (I've always thought that Spawn was some crazy Batman, Spiderman, Punisher, Ghost Rider cross over, heralded also by earlier stories still like Son of Satan and Satana).
If you are a fan of Gaiman or Spawn I would recommend this, if you are unfamiliar with the series or new to Spawn you can read this without requiring knowledge of the earlier comics or story arcs, I would even recommend it if you are familiar with the legion of action figures and small industry which were more or less launched following the success of these comics. Great stuff.