So is Michael Myers magical or just really tough to kill?
Not really sure how Myers' and the Halloween universe is defined, or what the rules are. For example, we now know after multiple sequels that Jason Voorhees is magical because he's reincarnated, dug up from the underground and revived by lightning, can survive underwater for weeks in a harbor, and can live through being frozen for hundreds of years by liquid nitrogen.
Same thing with Freddy. He actually exists in a parallel dream universe and can influence reality. No debate about that one, the writers got right to the point.
What about Myers? He's been shot multiple times, stabbed, hit with blunt objects repeatedly, fallen out of windows, and been burned alive in a basement cage. I guess its possible to survive all of that. I do not recall magic being involved, just that he is the essence of evil.