Thank you for the feedback! You have to kill it with the block. The shield enemy should go furthest to the left, and then you rewind the block to make it smash the ground again. That should kill it.
You said you already tried it, but maybe you didn't utilize the rewind mechanic on the block? Either way, maybe the puzzle should be easier..
Oh, and trying to kill it by rewinding the arrow is very interesting! We didn't think of it