This is Kieron Gillen's take on Watchmen both visually, thematically and verbally. The blood splattered smiley, the Comedian's plummet from his apartment, Rorschach's disintegration, Ozymandius's televisions and more are riffed on and recreated.
The essential vibe is what did Ozymandius do after the end of Watchmen.
In this story what he did is try to save alternative Earths from nuclear destruction, unfortunately resulting in their destruction due to repeated flaws in his play. In a clever bit of justification of his actions he points out that he is only villainous if he never succeeds, if he succeeds then the failures are the cost of success.
Peter Cannon's power of formalism allows him to exploit the conventions of comic books, such as moving through panels and creating covers to move between dimensions.
Ultimately it is a stay in a dimension based on Eddie Campbell's Alec comics (including appearances by Campbell and Moore) that provide Cannon the inspiration to defeat himself. Exploiting his lack of willingness to change his vision of perfection Cannon is torn apart by a three by three grid.
This is all highly meta and self-referential and its entertainment value depends strongly on how you feel about that. I thought it was clever and the recreation of Campbell's comics is uncanny but it also feels emotionally unsatisfying and too easy.