Among the differences that the excellent animation makes clear:
1. Lower case I (i) is made inexplicably ugly. Perhaps it helps legibility at lower rendering sizes, I'm not sure.
2. Parentheses have been moved such that the left paren is moved a little more left, and the right paren a little more right: this gives function calls an arguably more natural look if you like space around the arguments. In particular open/close next to each other are less awkwardly placed with the new spacing.
3. Underscore (_) has been made discontinuous, such that repeated underscores are no longer a single line. You might like this, you might not. The underscore character was originally intended to become a continuous line and used to underline letters (and by originally, I mean with typewriters and lead type).
4. Lower case R (r) has been moved left. This makes words like "try" more evenly spaced, but screws up "stderr". You can't have everything in a monospaced font.
5. Square brackets ([ and ]) have been moved left and right, like parentheses, for the same effect.
A lot of people seem to be slamming it, but perhaps it isn't all that bad.