... the turbo tunnel didn't have a boss fight. Do you mean the fight with Big Blag in the surfboard level? Yeah, he was easy peasy if you had a walker's leg to pummel him with, you could smack him against the side of the screen and just keep him juggled until he exploded.
Of course, that implies you took the warp right before the end of the turbo tunnel to skip the ice caverns... but I think just about everybody did.
Man, I remember a lot about old NES games.