This is my first jam also. And I'm struggling at such an easy theme.
Good luck, mate. :)
instead of using rewind on game use rewind on objects and set them to its initial stage coz that what rewind actually means
use it to put object to a decaying state or to a state when the object was healed, see god of war ascension heal and decay mechanism
rather than that use rewind as a weapon to put enemies to their initial position or objects to their initial position but keep your position unchanged thus this can also be used to design many different puzzles
ok all the best this theme is overwhelming to me also so good luck