Some people will think this is more cryptic, as it's more demanding (6)

I believe the answer is:

harder

I'm a little stuck... Click here to teach me more about this clue!

'more demanding' is the definition.
('hard' is associated in meaning with 'demanding')

I don't understand how the remainder of the clue works.

(Other definitions for harder that I've seen before include "More tough or difficult" , "More solid" .)

I've seen this clue in The Irish Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.