I finished this yesterday and what a mixed bag it is. The story and art direction are some of the best I've seen in ages. The U-Boat feels really lived in in the same way the hideout of the first one did but bigger and more detailed. The level design has some confusing decisions in terms of flow, but the arena areas are sick - the problem is, the gunplay is so weak that you never get to really traverse them in any kind of interesting way. DOOM had a great balance of push and pull in combat, and really pushed you to move around the various areas in order to stay alive and keep your streak going. In this, you're constantly getting mowed down in two seconds without realizing it until you're dead, and when you're fighting, you're constantly flicking the mouse down while hammering E so you can stave off death. The weapons are pretty cool, especially upgraded, and when the opportunity to use them in a relatively open area arises, the shooting can be fun, but for the most part it just feels weak.
That said, the story is so bonkers that I can basically put all that aside. The first one was over the top at points, but TNC is ready to just jump off the rails, then jump off whatever it lands of from there into outer space. I'm pleasantly surprised to see a game this big that's allowed to be this weird.