From my research, I have learned a good amount about thrillers and their sub genres. For example, I now know that most thrillers are based around suspenseful moments. However, in these openings, they never actually show any murder, just the build up to the scenes. This is in contrast to most horrors as they often do show that in their openings. Also, the opening scenes often try to establish the protagonist before anyone else. They then use this to build suspense for the rest of the opening scene