I found "800 balas" to be a very entertaining film, if a little juvenile. The story follows a young boy in search of his grandfather. Carlos' (the young boy) father was a stunt man who died in an accident before Carlos was old enough to remember him. He goes in search of his grandfather to discover the true story his mother refuses to tell him.
Carlos finds his grandfather working in a Wild West tourist town where spaghetti westerns were once filmed. The exploits Carlos and his grandfather get into are entertaining and full of action, although fairly predictable. Carlos' grandfather is played by Sancho Gracia who is probably the highlight of the film. He very convincingly plays a depressed alcoholic who dreams of the old days when he was a stunt double for Clint Eastwood and other Hollywood stars, while also harboring guilt over the death of his son (Carlos' father).
Overall the films is good, but not great. The action sequences are very well thought out and the director's somewhat wild sense of humor fits in well with the overall tone of the film. In particular the ending sequence skillfully plays on suspense, action and humor to bring the film to a satisfying and sentimental conclusion. The location of the film in central Spain is very beautiful and the film does a good job of using the landscape and incorporating it into the story. The film is worth watching if only for its pure entertainment factor and for Sancho Gracia's superb performance.