This is hard to define, as everyone has different goals.
For me, critical listening has a few steps.
1. How quiet the soft passages are the dark space
2. How different the soft from loud parts are, can a cymbal crash make me jump or surprise me?
3. Does each instrument have it's own space? Is it wide or narrow, are they crashed together or have their own space? Can I tell the difference between a bass drum and bass guitar?
4. Decay, does a bass drum roll off, does a cymbal crash linger?
5. Vocals, are they up front? present, "on stage" so to speak.
6. Balance, is everything in balance? Does anything take over or is it smooth from bottom to top?
7. Does it make me feel anything?