Eric Draven: Suddenly, I heard a tapping. As if someone gently rapping. Rapping at my chamber door.
Gideon: What are you talking about?
Eric Draven: You heard me rapping, right?
In the scene at the bar with Gideon when the black guy pours Gideon a drink it is only about 1/3 full. When Gideon drinks it in the next shot it is almost full.
When Eric first goes back to his apartment, right after he returns from the grave, it is raining inside the apartment and his movements look an awful lot like the movements he just made in the rainy alleyway. [Not really a mistake, but worth noticing - the filmmakers were forced to re-use some shots after Brandon Lee's death.]