- Susan's hair being extra

- Explanation for Susan hair nonsense (very next page)

Diane can do a backflip. Can Susan do a backflip?

No.

No, she cannot.

I originally imagined Diane being less confident in panel three, and trying to cheer herself up with the above backflip argument.

Then I remembered THIS IS DIANE.

Also, for real, she has some serious cheerleading skills that she worked hard to acquire (see previously mentioned backflip). Those might be mundane when compared to monster-slaying magic, but they're something to be proud of, darn it.

Susan's summoned sword doesn't normally have a visual effect like that, but Diane's imagination is allowed artistic license.