Puzzle is a successful Japanese thriller in the vein of Saw (but still quite different). It follows lonely teenager Shigeo who at first appears to be bullied (until we find out that everybody is actually being quite friendly to him). The reason for his isolation from society is the fact that he is a remorseless killer who plays deadly games with anyone he wants, in a couple of occasions even including the whole town.
The real fun begins when he discovers Azusa, a traumatized girl who only needs a small push to descend into madness. Fortunately for Shigeo, she is disturbed enough to actually join him after he exposes her to the roots of her past traumas (won't spoil anything here, don't worry).
The film is violent yet fun in the best sense, combining chaotic death games with innocent imagery, for example using cute sunflower masks to hide the perpetrators while they're reigning chaos across town and designing deadly devices that look like toys. There is no clear chronological order to the proceedings, instead the film is counting days until the climactic event (this complicates the film a bit, but it won't be a problem to most viewers). It's also commendable that the film lasts about 80 minutes, a rarity for a Japanese movie.
Some may be bothered by the lack of sympathetic characters, and the choice to leave a lot unexplained. It might have been a better choice to flesh out Shigeo and Azusa in greater detail than just offer simple explanations for their behavior. But it's no use complaining. This wasn't intended to be a philosophical, nor a psychological piece. We still get an enjoyable little thriller that doesn't leave a lot to be desired. If you're no stranger to Miike, Sono or Tsukamoto, or just feel adventurous enough, check this out.