In the original NES version of Bionic Commando, after rescuing Super Joe, he tells you where to get a "Special Machine Gun" from Destroyer 3. I find the gun to be completely useless, so I don't get it anymore unless I'm trying to do a run with getting all items. As far as I can tell there is no situation in which it is better than the rocket launcher; am I missing something?
A simple wiki search tells us that:
This is probably the only instance where Joe's Machine Gun is actually useful.