First of all, the Platinum Dunes remake has made $41 million over its opening weekend, already out earning every traditional Friday The 13th movie in three short days (it is still second in total gross to the $87 million grossing Freddy Vs. Jason). Hell, it's $19.3 million Friday number out grossed the domestic totals of Friday the 13th parts 7-10 (and the first day was within spitting distance of the $19.4 million gross of part VI... I'm surprised New Line and Paramount didn't pad it accordingly). Whomever those 'experts' were that predicted that this would do $20 million for the weekend... well, they should be jammed into a tree with a machete.
This opening is right in line with the $25 million+ openings for Marcus Nispel's The Texas Chainsaw Massacre and Rob Zombie's Halloween, adjusted for inflation, the perfect release date (why didn't Halloween opening on Halloween weekend, again?), and the general acceptability to mass audiences. Texas Chainsaw Massacre (accurately) had a nasty, gooey, painful looking trailer that promised blood, grime, and prolonged suffering. Halloween had a trailer that promised swift and horrifying death and sheer brutality (again, quite accurate). The Friday the 13th series has always been the 'kinder, gentler' slasher franchise. Yes there was blood and gore, but the deaths were quick, painless, and often more funny than scary (does anyone know anyone who has ever actually been frightened by a Jason film?). At a glance, the film looked far more appealing to the casual horror fan (the sort that enjoys the PG-13 outputs) than the previous remakes (it also helped that this wasn't a horror masterpiece being remade, but rather a piece of crap that happened to spawn a popular series).
Of course, the big trump card was New Line and Paramount's ability to actually open the film on Friday the 13th, the day before Valentine's Day no less. I can't imagine how angry Lionsgate must be that they had to open My Bloody Valentine 3D in the middle of January. Like The Omen: 666, this was a remake that seemed to have been created to capitalize on a release date. And like the Omen redo, this film is pretty much finished now that said release date has come and gone. The Marcus Nispel Jason remake had a pathetic 2.108 multiplier, which is just below the 2.13x for Sex And The City and just above the 1.935x multiplier for Twilight. Of course, those two didn't have a holiday weekend (tomorrow is Presidents Day) to bounce off of. I'd be shocked if Friday the 13th gets to $100 million, even with around $46 million likely in the bag by tomorrow evening.