Movie is captivating. If you can't figure what's coming.....you'll know at 31 minutes.
But ive always enjoyed movies like this....3 to 4 people...in one room for most of or half of the entirety of the film--
-- requires some really talented writing. Breathing in develops characters where everyone has something going on that you watch develop.
Slow burn? I guess....but maybe the clues came to easy.....(black finger-tips...an aversion to daylight.....you know....little things.
Not for the kiddies.....but an excellent horror flic.