Like many of the classic films of Georges Méliès, 'Bluebeard' is groundbreaking, surprising, and filled with fun camera tricks and special effects magic, and it is also, no doubt, one of his darkest films. It's one of the earliest horror films ever made, and it gets pretty wild, particularly towards the end in which Méliès just fills the screen with action and suspense and special effects and death and ghosts and so on and so on.
The first portion of the film is actually fairly comedic, which makes how bizarre and tense it gets later on all the more surprising, shocking, and uniquely amusing/entertaining. Much of the comedy is in the common vaudevillian and slapstick vein Méliès's films, whether they be science fiction, romance, fantasy, etc., often indulge in. It helps set a tone that is harshly shifted by the end in a very enjoyable and fun way.
Of course, it gets better once it becomes a full blown horror film. Images of hanging women and keys that grow and shrink and spirits and an extremely energetic devil come and go and it's surreal and extremely impressive for the time. Méliès experiments with the overlaying of images atop other images, an effect we now take very much for granted, in a very thrilling nightmare sequence, and the jump cut tricks and theatrical bursts of smoke are very much in the vein of many of Méliès's other fantastical shorts.
