The film centers on a group of friends preparing for a party who find themselves trapped at a dance hall as they discover their missing guests have been murdered by a killer seeking retribution for an event that occurred during World War II; they struggle to survive. This is certainly among the best slasher films ever made. What works so well here is how it tells a straightforward story but manages to create something consistently engaging, which is quite an achievement. The film maintains interest throughout and features several excellent scenes of stalking. The initial attack on the couple is effective, the bathroom sequence stands out with its near misses and playful banter leading into the mistaken shower scene, the poolside pursuit of the couples leaving the dance hall is entertaining, and the suspenseful ambush as a couple is stalked in the basement is very well done. The stalking scenes are truly exceptional; the chase through the dorms, navigating different levels without revealing the killer’s identity through the hallway designs and ultimately leading outside, the search for clues in the killer's house while shrouded in darkness, and the encounter at the graveyard with the gravestone discovery and open grave all contribute to a great suspenseful scene. The final confrontation is also top-notch; the methodical search of the bedroom alone makes it enjoyable, being one of the film’s best suspense sequences, and the ultimate kill is spectacular. A significant element is that the killer remains largely unseen throughout most of the movie, relying on subtle clues to maintain secrecy until the final reveal. The focus on keeping the figure in shadow is another effective way to build tension. Combined with the impressive gore and kills, this film ranks among the very best in its genre. It has only minor shortcomings. The relatively low number of victims—failing to reach double digits despite the potential for many more deaths—is a bit difficult to accept. While the graphic nature of the violence makes it hard to discern, adding one or two more kills wouldn’t have hurt the film. Also, the killer's suit feels somewhat contrived; while the military uniform has relevance to the backstory, it comes across as an attempt at originality that doesn't quite work. However, these issues are insignificant and don't detract from the overall quality of the movie. Rated R: Graphic Violence, Nudity, Graphic Language and a mild sex scene.

Source on TMDB