I didn't notice that the mask wasn't expressionless, but now that you mention it, it does look like it's either frowning or angry. Also, though I know he goes without a mask for like half of Halloween 1 (RZ) as a kid, I don't really like that it looks like most of the ending has him with only half a mask on. Come on, in the originals we barely saw shadows of his real face. One glimpse in Halloween 4, that was it.
And for that split second that the girl managed to rip off his mask in Halloween I before he got shot 6 times, burned, stabbed, run over, blown up, shot some more, and oh, did I mention falling off a balcony. That's why Halloween scared the **** out of me. He always died in an inconvenient location and when they went to go get him, he was gone.
Yeah, Michael's a badass motha--....Oh Michael killed the girls that were supposed to say "Shut yo mouth."
You know, one sure fire way to kill Michael would be to maim him. Cut off his arms and legs, he may still live but what's he gonna do? He's a torso. Gonna bite you to death? ...Did I inadvertently make a Monty Python and the Holy Grail reference? Hm.
He could probably also die from beheading like Laurie thought in H2O (Though that wasn't REALLY Michael. It was some paramedic, I think, that Michael disguised and cut out his tongue....God the movie that followed was such a disappointment. 10 minutes of crazy Laurie and then she gets killed only to have it turn into a slasher movie with no point. And personally, I would've loved to have seen Jamie as a serial killer...But she never existed apparently...*eye roll* Ah, getting off my point.)
Other than that, I don't think Michael ever dies....
There was that one time in Halloween 3 where the police actually got to him, like 20 feet away, but then he fell down a conveniently placed hole and escaped. >=O