Do I need to watch part 1 first?

Nope. Same applies to the third one.

Awesome funny movie and i think the best part of this „trilogy“.

Yeah I was going to say the III one is surprisingly good. I used to know the director and he was super cool. Also produced re-animator. He also did a weird low budget movie called "society" which is interesting.

There are a few horror and sci fi movies with similar themes to Society that all came out around the same time. Society is probably the wildest. Worth a watch.