Hmmm. I have a theory about Re:Zero.
Every time Subaru dies, it's not that time has rewind, but it's probably he restarted in another parallel world.
For example, in episode 7, Subaru jumped off the cliff and died. Time did not rewind, time still moves on in that world, and Rem is still dead. Subaru is just gone into another dimension or world where Rem is still alive and save her there. Same thing to the other deaths.
Idk. Just a weird theory I made based of Steins;Gate and the John Titor ****.