I did a very rough calculation, based on the damage I did on him.
Assuming the assumptions I made were valid in some certain degrees, I think this guy has 270,000hp minimum on hard difficulty. The exact number isn't important, the point is this is rather ridiculous, don't you think?
It took more than 2 hours to finish the whole thing and Part 5 alone took about 50% of it.
It gave me a very uncomfortable WOW feeling.
This is not WOW, isn't it?
-Nirv