Just finished Cognition. Really, really, really enjoyed it overall, so here's a (possibly too) detailed breakdown.
Things I liked:
-Great voice acting. I'm decently critical of acting in games and I find myself constantly wondering "Well, if the line were delivered this way, I feel like it would get across the tone better," and I don't think I did that a single time throughout the game.
-Great music. I loved the addition of The Scarlet Furies as well. Great song and it made the whole world feel more rounded out and alive.
-Mostly fantastic puzzles, with a few exceptions. The interrogation scene, like everyone has said, played out really well. I felt good for solving it, and that's always the ideal with adventure games. There is no worse feeling than "Seriously? How on earth was I supposed to figure THAT out?" after clicking random things together.

-Reminded me of The Longest Journey. I can't put my finger on why. Maybe it's the combination of the present setting plus supernatural elements, maybe it's just the fact that the puzzles feel like adventure gaming gone right, but regardless, it's a great thing. I've never played Gabriel Knight, which is apparently the more commonly cited inspiration, but still.

-The hint system was really cute. It was usually very aware of what state the game was at, and that was very helpful. The one complaint I have is the persistent request that I take a picture of the tattoo. I did. And I didn't even use it this episode.

-The multiple solutions! I didn't even realize it on my playthrough but reading through the hints section, I really like the alternate puzzle solutions you guys set up. Things like needing Davies' "interrogation mug" or Terence not wanting to help you were things I never experienced, but I love that they exist. I always love it when two people can play the same game and discuss it and have vastly differing experiences (this was one of the things I loved about Heavy Rain). Obviously you were limited in what you could do (certain things clearly still have to happen), but the fact that the puzzles had different solutions, and it's not just that the dialogue was different really stuck out to me as great design.

Things that took me out of the experience:
-Needing to find change for the vending machine. I know it wasn't much of a puzzle, and the "solution" was fairly simple, but I couldn't help but think "Seriously? I am a grown woman and you're telling me I don't have a wallet on me?" It just bugged me that we had all of the logical things for Erica to keep with her (cell phone, badge, gun), but no wallet.

Also, then having to bash the machine to get the chips out, was that meant to set a tone? It's fine if it was supposed to create an atmosphere, and it sort of did that, but my first instinct was that you were just making me click more.

-This got mentioned before, but the weird loading times when you learn about projection. Maybe I should've remembered what Scott looked like, but clearly I wasn't the only one to forget, so that basically brought it down to trial and error, and there was a several second delay between each try. I didn't need to read the tutorial again, I just needed to try again.
-Related to that was the conversation with Sully in the apartment. Having to click through the entire conversation every time I messed up during the end was really, really tedious. I know it'd make it easier for mindless trial and error, but what about Sully going "No, something doesn't seem right," and then re-asking the question you just got wrong? I feel like that'd be a lot more engaging than the obviously metagame concept of clicking through dialogue I've already seen. Also, if I say "I need to look at some things, give me a sec," that should not count as failing the dialogue. I made the cautious decision and I should not be penalized by having to start that entire "puzzle" over.
Minor nitpicks:
-Erica's accent. At first I thought it was a Boston accent bleeding through, but then I realized it was probably
supposed to be a Boston accent. It just seemed a bit unnatural. The acting was still spot-on, but things like turning all -ing words into -in' words and ending "er"s into ending "uh" sounds just seemed very forced.
-A couple interface quirks. First off, like some others have mentioned, Cognition powers felt a bit off. Why not just have the respective Cognition power activate after the requisite amount of things have been clicked on? For projection, all you'd have to do is just make it so if the improper things were clicked on, just give the error message and leave the things highlighted. That way the user can unclick one of them and then the game can go back to detecting when 3 have been reached. I'm not sure exactly how the system is implemented, but from a pseudocode point of view it doesn't seem like it'd be too hard.
-Combining items. Unless you're really familiar with prefix notation, "item + item" is a lot more intuitive than "+ item item". I get that you were going for consistency with things like needing to click the hand icon and then the item, but I think clicking the item and then the plus and then the other item would be a lot more intuitive.
-The map. I'm not really sure if the eye icon on the map really did anything but make me click twice. I know it's a morgue; it says morgue right on the map. I don't think it ever gave me any additional information. Also, this meant that the "Back to Boston overview" button also had two options when you clicked on it, and that was
definitely unnecessary. I just think it'd speed it up a bit if you could just click on the location and go there.
-As others have mentioned, the spinning wait icon. The only reason it really serves a purpose is if the game looks like it should be taking input but isn't, like if it's in an animation of, say, opening a drawer and taking something out. Maybe the game is loading the animation and not doing anything yet, so the wait icon lets me know that "yes, I have seen your input and yes, I am doing something about it. Just give me a sec," and that's helpful information. During things like cutscenes or dialogue, there is stuff going on that clearly lets me know the game is doing things. People are talking or images are coming up on screen. It's redundant and, like people have said, it gets in the way.
-I've never seen the name Terrence spelled with only one R. Obviously this is just a choice and not an error, but it still stuck out a bit to me.

Other comments:
-I, personally, loved Terence. It was a bit of a tone break from the rest of the game, but I liked that.
-While the swearing didn't bother me personally (probably because I watch quite a bit of Dexter too

),
frontloading the game with it might've been a bit of a poor choice, since it clearly put a few people off.
-I think I'd have to agree that UI issues stick out a lot more when you're looking at it from a design point of view.

-A log function would be crazy helpful, especially during that Sully conversation I mentioned earlier. There were a couple questions he asked where I went "Wait, I know Sully mentioned this as soon as I told him about the files, but what did he say?"
-Sully may have been a bit one-dimensional, but I thought he was cute.
