The Howling

The Howling is a 1981 horror film featuring werewolves. It's definitely dated and hasn't aged well. It has multiple werewolves and onscreen dramatic depictions of the transformations. I saw some actors I know from their other work: Patrick MacNee, John Carradine, Slim Pickens, Robert Picardo (Star Trek connection) and Noble Willingham (Star Trek connection). Roger Corman and Forrest Ackerman have cameos.

trailer:

1000 Misspent Hours says,

The Howling is such a potent reworking of its age-old subject that it’s easy enough to understand how it could spawn six or more sequels over the next fifteen years.

Moria gives it 3 stars. Roger Ebert gives it 2 stars and a review that's one of the least informative I've ever read.