Bosses do things more often, sometimes not respecting your precious 2 min windows.

Tells are more 'Chimera' or 'Coincounter', less 'FATE boss'.

Someone is more likely to wipe or die the first time they try, thus proclaimed 'difficult', nevermind still being able to succeed in a timely fashion.

Trash sometimes does 'something' rather than 'nothing'.

The speed of the encounters, from how often mechanics come to how quickly they combine (i.e. shorter 'tutorial' phases' is the single greatest thing to spill out of Criterion.