Editing: Brightness and contrast

My group and I watched our thriller a number of times when we thought we had completed it and found some small errors. 

For instance, we made some transitions smoother and some sound louder where needed, but we also change the brightness and contrast of some shots. We changed this because we felt the transitions would be smoother and our thriller on a whole would slightly more professional. For example, we darkened our first shot and lighten our second shot in order for the first two rushes to cut smoother and work better together.