If you have the time, check out a few of the articles in the Spring 2002 edition of South Atlantic Quarterly, which is devoted entirely to considering 9/11 and its aftermath(s) from a critical perspective. It’s volume 101, issue 2, and the journal is accessible online through GMU’s library (off-campus access).
In particular, check out the provocative essays by Fredric Jameson, John Milbank, Susan Willis, and Slavoj Zizek.
Also, I recommend DeLillo’s essay "In the Ruins of the Future," which first appeared in Harper’s in December 2001 and is also available at the Guardian as well.
These readings, though not required, will definitely resonate with Spiegelman’s own account of the happenings and consequences of 9/11.