Should I watch this ??

Yes... it is excellent, very underrated, well acted... A very unique type of horror film.

Kind of a surprise ending ( to me anyway) an I am old enough to have seen thousands of them

Yes. Kind of a forgotten movie, but it's very good.

Yes!

If you like good movies, subtle satire, old horror movies, silent movies, or weirdness, of course. If you like Michael Bay movies, it might not be for you.