Now this is the kind of cheap, shitty horror movie I sort of expected from surprisingly decent Christmas horror entries Black Christmas and Christmas Evil. While those movies offered a level of inventiveness, character development and attention to detail that elevated them above their gimmicky premises, Don't Open Till Christmas does everything possible to live down to its limited budget and exploitative concept. It's poorly acted, lazily written, edited as if by gardening shears and suffused with an overwhelming air of sleaze. In short, it's a typical '80s quickie slasher movie.
The premise here finds a killer stalking the streets of London just before Christmas, killing various people dressed in Santa outfits. Now, you'd think that if a psychopath was wandering around killing anyone dressed like Santa, people would stop wearing Santa outfits, but that's clearly not the case here, and the killer has no shortage of idiots in Santa costumes to murder in various gruesome ways. We also follow a pair of detectives investigating the crime and a few survivors who were witness to the Santa-cides. Naturally, everyone is a suspect.
There's no effort made at narrative coherence or character consistency, and the pacing is choppy and sometimes confusing (often scenes seem to end at random with abrupt cuts to new locations). The movie actually has a credit for "additional scenes written and directed by" someone other than the credited writer or director, and apparently the original director (who also stars as one of the cops) walked away from the movie before it was finished. So the slapdash structure is partly due to outside circumstances, but that doesn't make it any more entertaining to watch.
The filmmakers provide distractions via lots of really fake-looking gore and a generous helping of nudity, but it's all rote and not particularly creative (other than an infamous scene in which the killer slices off a Santa's penis while he's at a urinal). The "twist" ending is laughable and completely obvious, and none of the violence has any impact. It's enough to give senseless mayhem at Christmastime a bad name.
The True Meaning of Christmas: Be careful when you go out in that Santa outfit.