It’s an interesting and noteworthy entry within its specific type of movie, and feels genuine… but I didn't find it amusing. I don’t generally care for mockumentaries, though I understand their merit if they are humorous. The story follows a British rock group called Spinal Tap as they go on tour, depicting the considerable challenges and unusual events that happen both onstage and behind the scenes. It intends to be a comedy... but truthfully, it didn't elicit any laughs from me. I acknowledge the significance this film had in establishing its subgenre, and how it might interest those studying filmmaking or exploring cinema more deeply. For someone like me, who simply enjoys watching movies, it’s another matter: I’m less inclined to rewatch it because of all the technical points that could be raised about it. As a comedy, it needs to be funny. If it isn't, then it didn’t succeed as one – even if I might not be who it was made for; that would just indicate it’s not a film for me. Even though I didn't laugh, I do appreciate Rob Reiner’s direction and the sense of realism he brings to every aspect of the production. I'm curious about his preparation – did he interview music journalists, bands, or artists? Because the movie really does portray the strange occurrences that can happen on a rock tour. The performances by the lead actors (Michael McKean, Harry Shearer, Christopher Guest) are also commendable, especially considering much of their dialogue is improvised. The film has a low-budget feel, which may even be deliberate: the camera work resembles a “found footage” style with shaky, poorly adjusted images and occasional graininess. The sets are very well done, and the original soundtrack sounds completely authentic.

Source on TMDB