TV's Frink said:
Ghostbusters 2 is the worst. The OP has vastly overrated it.
I consider those films listed to range from average to terrible. I do enjoy some of them but I don't think that alone makes them underrated at all.
Movies like Predator 2 and Die Hard 2 definitely didn't go under the radar, but now I kinda wish they had.
I would suggest Primer and Brick. Interesting films, Both with great reviews that people just don't seem to be aware of.