Franchise Killer: This movie brought down both the original Tales from the Crypt television series (which had just been Uncancelled) and the film series as well after its poor reviews and box office. As a result, an eventual third installment (Ritual) went straight-to-DVD and initially had its ties to the franchise edited out. Another film (Fat Tuesday) had a completed script, but was canceled in pre-production. (Word Of God, though, insists that was due to other factors.)
However, they do mention in Demon Knight that there was more then one key (in-fact SEVEN of them), and its possible all keys look like that.
Also the end of the world was only if the demons got all the keys. Maybe this means we're permanently saved!
It is meant to be one of the keys, one was supposed to appear in each Crypt movie, but it didn't appear in the third film. The destruction of this key would also explain the Cryptkeeper's assertion in Demon Knight that Jerilyn lives happily ever after.
Recycled Script: The host segments here are almost the same as the ones from a fifth season episode, "The Assassin"—even reusing guest star William Sadler! (Though he plays a mummy here instead of the Grim Reaper.)