Postmodern theories tend to argue that modernity has ended or that modernity must be rejected completely. 

Critical theorists tend to theorize extensively and some argue that politics can be used to pursue progress.

Post-modernists may even reject social theory and political practice.  

Critical Theory is more likely to be associated with rejection of comprehensive, universal theory.

Critical theorists generally tend to have an idea of progress for the better, even if they are unable to find ways of getting there.