Henry is doing a maze puzzle when Roy and his thugs walk into the bar. But after they talk, it soon changes to a crossword puzzle.
After ramming the first victims car into the water, causing visible damage to that car, Johns GTO has not a scratch on the front when it pulls up in front of the house two scenes later.
At the end of the movie, after being shot in the center of the forehead and dying, after several minutes of laying on the ground, Jennifer Tilly can clearly be seen breathing.