The second movie ends up feeling the most different of the 1st five. It has a male protagonist and is famously homoerotic. It's also less about dreams than most of the rest of the series, and the horror tropes it adopts remind me of a werewolf movie.
It does contain the moment of pure WTF?
As I'm sure you know, IV is directed by Renny Harlin. It has alot of the series most imaginative set pieces, but it doesn't have the sincerity of the movies Craven was involved in.
V has a few good set-pieces and some viable ideas, but it was made by a bunch of hacks, so most of it is just kinda boring.
VI feels like fan-fiction conceived by an 11 year old. It's horrible, and it manages to be nothing like the preceding movies while being obsessed with their "mythology." Roseanne Barr, Tom Arnold, and Alice Cooper all have cameos.