incremental backup files

I'm using the incremental backup and the size of the incremental backup seems to be fairly large - can you tell me how I can determine the file names that were backed-up with the incremental backup - when I look at the backup file (with windows explorer) I see all the files listed and I know most haven't changed since the full backup. I believe I can reduce the size of the incremental backups by excluding some system files, but I don't know which ones.

Again, how can I determine just the files that were backed-up using a incremental backup?