Most corners are more rounded by default, especially buttons, which are pills now instead of rectangles. You could make them pills before and they offered examples showing how to do it, but hardly anyone did.
Buttons are a little bigger, and there's a little more padding between most things.
There are more transition effects, making apps feel a bit more fluid and "interesting", in a good way, I think.
Nav bars and rails do a much better job of highlighting the active item, by adding a pill-shaped background behind it. (This one addresses a frequent complaint that I received when using material components on websites.)
The rest is somewhere between "exactly the same" and "really minor", but the minor changes vaguely contribute to a different feel from before.