It killed a lot of planes. Especially as a night fighter. The leading Japanese ace Saburo Sakai was nearly killed by some Grumman Avengers. He rolled in on them from the rear thinking they were Wildcats, when his windshield exploded. A ball turret gunner shot him in the head.
There was a learning curve at the beginning of the war. The Germans thought the Stuka was badass, they terror of Europe, until they tried to use them over England one day.
There was some Japanese fighter which had a gun installed behind the pilot pointing upward at a fixed 45 degree angle. It would drift in behind a flight of bombers above and let lose from below. Apparently, the bombers seldom knew from where the attack was coming until it was too late.
Didn’t we have a twin engine night fighter that looked kind of like this?
Black Widow?