In all of the early video editions, at the very end of the movie when Michelle closes the truck door after Benny gets in, the sound of the door slamming shut is heard before the door actually closes. This has been corrected in the recently reissued version however.
At the climax, the chainsaw falls into a small lake/body pit and slowly begins to sink. First of all, the chainsaw's weight would have caused it to sink almost immediately, not slowly. Secondly, somehow the chainsaw continues running despite the fact that no one is giving it gas and it is partially submerged in water.