Why didn't David Tennant tell Charlie Brewster that the unicorn he was riding could stab the vampire to death with its horn? A better question is, why does a movie supposedly set in this day and age relentlessly hammer away at the supposed hero's virginity? (Which the supposed heroine isn't, by contrast.) The conviction that fanboys don't like sex is set in concrete in Hollywood.
The original Fright Night was one of the cinematic pioneers of the sexy vampire (along with Vamp, Frank Langella's Dracula, Interview with the Vampire and Lost Boys.) That well's been drained dry.
The unbelievable hostility between all the characters (well, strictly, Toni Collette doesn't respond to Charlie's dismissive attitude with anger or bitterness,) means all the positive actions they take seem unmotivated.
Colin Farrell was impressive, David Tennant was delightfully funny, Anton Yelchin was there and Christopher Mintz-Plasse entirely failed to make his character seem human.
Poor stuff. Sorry I wasted the money.