Part 2 is awesome & one of my favorite parts. I think Part 1 just doesn't feel as "bizarre" or crazy compared to what we see later on if you compare it to, say, Part 2. It's good, but when you see what happens in future parts, it doesn't stand out as much.
I think it's only considered "unpopular" because it gets overshadowed by its predecessors. Probably also helps all future parts are MUCH longer in comparison, so you get more characters, enemies, powers, fights, etc. & sticks with you more with all of the different moments it has.