Let's be honest. The Blair Witch Project was not a great horror film. The Blair Witch Project was an event, a cultural rarity that impacted our society in a way that few other events like it have. In my mind, the next closest event to The Blair Witch Project would be the Orson Welles War of the Worlds radio drama in 1939. War of the Worlds was done with only a minimal statement about it's fictitious nature, and people tuning in who missed the opening thought they were listening to a regular radio broadcast being interrupted by actual news reports of invaders from another world. The Blair Witch Project had the same impact, suggesting that it was edited together from film evidence of the last days of three college students investigating the myth of the Blair Witch in the woods of Maryland. The production quality is raw and the editing rough to encourage the realism of the films premise. Viewers are drawn in and made to believe in the film's reality. I remember hearing outrage and disgust from those who saw the film in theaters regarding the scruples of a production company who sought to profit from the tragic and mysterious disappearance of these young people.
Never mind that they were being interviewed on Conan and Letterman.
Many people believed that the event depicted in the film were real. The mythology of the Blair Witch was well crafted, and the Sci-Fi Channel got involved, co-producing a supporting documentary based on that mythology. To this day, people still travel to Burkittsville, Maryland to go on Blair Witch tours and to get scared by noises they hear in the woods.
Because of the nature of this film, it is only scary... only disturbing once. Like a magician who reveals his secrets, once the viewer confirms that it is all fiction, then the film becomes ridiculous.
The Blair Witch Project was innovative not just for its premise. Most of the film was shot in first-person; one of the actor's shot the majority of the film themselves. The direction was minimal; the actors were given a general plot and script and were encouraged to ad lib. The actor's scripts also including conflicting information, or parts of the plot were known to one actor and unknown to the others. The actors were sometimes intentionally abandoned by the crew, and were deprived of food and sleep. Much of the frustration caught on film was real. During many days of filming, the actors were actually lost in the woods with no clue what they could expect to happen next.
Another wonderful aspect of this film is the lack of a "reveal". Some of the best horror films in history never reveal or only partially reveal the antagonist. The harrowing experience is shown, but the enemy is always kept in the shadows, leaving it to the viewer's imagination to fill in the details. The Blair Witch is never seen, only felt based on the evidence of its impact on the three actors and the strange phenomenon that is filmed in the woods. In the end, the viewer is left wondering what happened, knowing only that the three lives they witnessed represented people who were now missing and that what happened may never be known.