The words I kept seeing in relation to this DLC from people were "IP Abandonment", and they couldn't be more apt.

It feels like the devs resented the game after the general reception, and decided to just put an end to it, but it's done in such a poor predictable way that it's laughable. A twist you can see coming a mile away because from second one nothing makes any sense and you're told to just ignore it. Even putting a sweet hammer in your hands and letting you pulp enemies can't save this mess.

While I was laughing at how crap the ending was, they tried to get a laugh out of me in the post-credits and I went stony-faced.