Right after the second aftershock when Heather Langenkamp sees the three cracks appear in the wall she runs down the stairs and is wearing only black nylons on her feet. When she bends over to hug Dylan she is seen wearing powder blue slippers; then in the next shot after she comes back from calling Jason at the door, the slippers are gone again.
During the final scene when Dylan is in the furnace, he has to push aside a snake to escape. The snake is exhibiting a rattling sound. The actual snake is an immature albino Suriname boa constrictor, and they do not rattle. Only rattlesnakes give off that sound as a warning.