Diaphora is a tool that can plugin to a disassembler such as Radare2 or IDA Pro that gives the ability to DIFF two different executables.
This has a number of advantages for reverse engineering:
So for example this can be very useful for comparing a beta build of a game that contains symbols with a retail version of a game that is stripped of symbols.
It can also be interesting to see what bugs have been fixed between different versions of games and they can give hints as to how the game works, especially useful if you also have the release Notes.