The keep: Good or bad?

[Zardoz!]

One of the damnedest movies I've ever seen was "The keep".

The thing about it is I can't decide if it was a good movie or a bad movie.

Every single element of it was great. Plot, cinematography, special effects (for the time), acting, dialogue, atmosphere, music... All the individual elements considered individually were excellent.

Yet, somehow, in some way I can't quite put my finger on, the movie as a whole was just less than the sum of it's parts.

Anyone else have trouble fitting the keep into a category?