Okay, so finished the DLC. Took my time to explore and got a good number of collectibles, took me close to four hours. I would place the DLC at around 3-4 hours, unless you really booked it, which you could probably do it in 2 hours. There's two difficulties for the DLC, you unlock the second when you beat it, tested it a bit, and it makes literally everything completely pitch black, except your flashlight.
Now, three things I will say before I say full impressions:
01.) The DLC is almost entirely stealth, story, and puzzle based. You only get a gun in one small section, and then lose it, you can find axes, but they're for you to execute in stealth mode, as you can't stealth kill an enemy unless you have an axe on hand, can't use the axe otherwise).
02.) Almost everything in the DLC is brand new, about 4/5ths of the locations you visit in the DLC are new, most of the enemies are new, the returning enemies and areas also have new touches.
03.) The DLC did actually answer a lot of questions, and at least the Assignment part didn't raise many. Not everything is revealed, though, and there is a second half of this DLC coming out later this year (The Consequence).
Firstly, the story is a HUGE improvement over the original game's in my opinion. I liked The Evil Within, but I felt story was its weakest area. I think the way they told the story in the DLC was a huge improvement, they managed to be cryptic but not undertelling, and managed a creepy tone that shed light on things, and kind of reveals a lot more through both gameplay and cutscenes. Story had a much bigger presence than in the original game, but not so much so that it felt meddling with the gameplay. It also made me like Kidman, which is saying something as I just didn't care for her all that much in the main game, and sheds a lot more light on who she is and where she's coming from. However, it also sheds a lot more light on Jiminez and Ruvik in particular, seeing sides of both of them you never really see in the main game. I actually found Ruvik a lot more sinister here than he seemed in the main game, but the DLC also introduces a new villain, which if I may say, in my opinion trumps Ruvik by a long-shot (I didn't hate Ruvik, but he wasn't a 'great' villain in my opinion, the new villain n the DLC is much more interesting for me). It also fit in well with the main campaign, and made me rethink a lot of things.
The DLC actually had several puzzles. None of them were brain-stumpers, but were enjoyable, more so than the original game, it was a nice addition in my opinion.
Now, besides the story moments, puzzle moments, some exploration moments, and a single scene where you had a gun, this DLC was entirely stealth based, so it lives or dies by its stealth. Thankfully, the stealth was so much better than the main game, had a number of improvements. The Haunted look as they normally do when unalerted, but when they're somewhat aware their faces and scars begin to glow yellow, and when actively chasing you, will turn to red. However, they managed to mix up the stealth sequences so they didn't feel too samey, which is a nice touch, with introductions in very different level design, different enemies with different searching behaviors and styles, interesting boss twists for stealth, traps, level gimmicks, enemies that are blind but are super sensitive to sound, you can now take to cover to hide behind things and call out to summon enemies, certain context-sensitive things to help like calling a phone, and so on. And you're defenseless from most everything besides your melee, which any players of the original game can tell you, is night useless. Stealth kills also are not an option unless you pick up an axe, which you no longer use as a one-shot kill, but as a limited supply of stealth kills you can do.
I also will add this: Health regen does not matter. You get killed in one or two hits, and the regen takes forever, basically what would usually happen if I would get hit once, either die or be limping so I couldn't run, which would usually lead to me getting hit again anyways, with a few rare exceptions.
There's a lot I want to say about specific moments, like the original game, there was some mixed bag here. The lowest point for me was the beginning of Chapter 2, which was a sewer area, but once out of the sewers it got much better again. My favorite part of the DLC probably goes to two stealth boss battles in the DLC, which were well done and fun, though the second one definitely wore its inspiration on its sleeve.
It actually managed to scare me a few times more than the main campaign did, and some of the moments I would say rival some of the best down-time moments from the main game, though the action and gunplay was missed in some places, but the stealth here definitely saw much improvement to the original game, and was enjoyable as such, along with the much more enjoyable story and puzzles. I'd say worth it if you liked The Evil Within and the idea of it being stealth-based does not bother you, know the stealth has seen much improvement and there is still a lot of variety here even with that, surprisingly so I would even say. They pack a lot of ideas in that 3-4 hours, and surprisingly most of it isn't recycled stuff from the main game.
Also, the fucking Light Lady turned out to be far creepier than she has any right to be, I think for me she may be the creepiest enemy in the game. She sounds goofy on paper (armless woman in red stilettos wearing a sheet with a lit-up divers helmet), but how she moves, her sudden changes in speed, the sounds she makes, and her fucking death animation, are creepy as hell, and she actually unnerved me on just being herself alone.