The bad audio + video quality
Okay, I just checked out a clip from badmovies.org(which inspired me to rent the DVD). Yes, there is absolutely no doubt to the fact the DVD version is awful. Wherever badmovies.org got their clip from seems to be a lot more "remastered" than this was.
But, allow me to play devil's advocate here. I actually kind of like the splotchy video quality and audio quality comparable to a bad record. It helps me into the 1980 mind set where all films looked like that to me.
Heck, even the reel change "pop" is left intact on the DVD version. Look no further than a neglected film that never got the filmguard treatment, or countless hours of digital restoration, and here it is.
Yes, I prefer the grainy film quality. There, I said it. If I was a big time movie producer/director and made a movie set in 1980, I would pay extra to make a film look this bad. There you would get the full illusion.