Difference between thriller and horror -

Rec is a horror for a number of reasons: The film contains a huge amount of blood and protrays more gore then suspense. This is consequently different as shown in Phone Booth which is dragged out and we feel some sort of emotion towards the protagonist as there is generally only one compared to a horror where there are generally many characters and these usually die unexpectedly. The music used is normally a lot deeper and it may just be diagetic sound compared with a thriller where there is no foreshadowing through the music.