Revealing mistake: When Ryuuichi gets the "fireball" at the end of the movie, the motion of the ball (Computer Generated) doesn't always mach Ryuuichi's hand motions.
Revealing mistake: When the man accidentally coats his hand in breading and cooks it in the boiling oil, you can tell his hand has not been damaged at all. The breading on the outside is just a little cooked, but his skin underneath seems perfect.
Revealing mistake: When the man raping the busboy is killed, in the first shot, you see blood starting to splatter onto the back of the busboy's neck/shirt, but when the camera cuts to closeup, there is significantly more blood on him.