Grinchy
Banned
I thought this too until I realised you also need to be shooting him to slow him down, keep one gun on him and the other on barrels and above. Made it pretty simple in the end leaving a big gap between me and him.
Ahhh, ok I guess I was doing that naturally the first time then. The previous boss was the same way where if you weren't doing damage fast enough, it just killed you with a wave of birds that you could usually kill but in this case were unkillable. I love this game, but some of its mechanics are frustratingly unintuitive.