Despite Freddy being laid to rest at the end of Part 3, the films had made far too much money for New Line Cinema to let things end there. So, through some plot contrivance (a Dog un-holying the holy ground where he was buried), Freddy (Robert Englund) is ressurected and starts where he left off, picking off the surviving members of the previous film.
He also turns his attention to a new bunch of teens, in particular young Alice Johnson (Lisa Wilcox), who for some strange reason seems to be acquiring her former friends talents (and bad habits) after each one gets killed.
With Freddy working his way through the main cast, each becomes as predictable as the next, with each of Alice's friends starting to nod off, then quickly snapping awake again (signalling to us that they're actually asleep) before Freddy pops up and, following a brief struggle, they end up getting killed.
Ultimately though, Alice manages to use the powers she's acquired to defeat Kruger (at least until the next film), which she does in a most unfathomable manner during the climax, which really makes you wonder what the hell was going on (God this film is sooo 1980's).
Directed by Renny Harlin, I'd say this is about on par with Part 3. As far as sequels go it's an OK film, its relatively enjoyable and the hard rock soundtrack is kind of cool, but in the grand sceme of things, there's nothing really outstanding to recommend this, unless your a die hard fan of the series then you'll probably love it.