You're allowed an opinion...not entitled
If you did not like at least HALF of this movie, you have absolutely no appreciation for the genre. Don't get me wrong, a sequel would be a bad idea and those two know that and I highly doubt they will do it. Leave a good thing be.
I have not paid for a movie in years except the occasional kiddie flick with my 5 y/o but I paid for this on VOD for $8 in HD. I've not felt suspense like when Derek being chased several times and feeling his struggle to get away from the "enemy" but also an unknown affliction that he so desperately wants answers about...