The new 2-DISC set of SLUMBER PARTY MASSACRE: THE TRILOGY released by SHOUT FACTORY is everything a fan could ever want. It has commentaries by the cast and crew on every film, an in-depth hour and change documentary on the making of all the films, and a vaguely remastered picture.
I bring up the vague part, because PART 2 still has the crappy sound that my partner in arms (and SPM super-fan) Adam 'The Riot' Thorn has been listening to since he got his first VHS copy of the film. I'm sure that SHOUT FACTORY did its best from the material it could pull out. The films were never meant to be seen in pristine condition after they hit theaters, and any complaints are mere nit picks against this amazing package.
If you're a slasher fan, or just a little curious, take the time out to check these out! Even if you're not a huge fan, the conceptualizations that the SPECIAL FEATURE add are worth the price of admission.