Finished Shin Megami Tensei: Nocturne late last night. I have a lot of things to say, so lets start out
The good: Great atmosphere and visual aesthetics in most areas of the game, really fun and fast combat system (especially for it's time!) which still holds up. The music is really good and help sets the mood. So many cool boss fights where you have to really plan out going in. Really unique from your regular RPGs where romance and friendship is key to winning the day. This game is 100% nihilistic through and through. Amazing artwork I wanna buy the artbook for right now!
The bad: The dungeon design is fine in the beginning, but come the end of the game they start getting just needlessly frustrating with gimmick ideas just designed to troll the crap out of you. I had no problem watching guides and looking up the overall map for a lot of these, and you should not either. The fuse system is also pure pain in the original PS2 version which I played. When you fuse two or three demons together in the HD version, you can choose which skills from the two demons you want carried over to the new demon, in my PS2 version, the skills carried over are randomized, meaning you have next to no shot of getting all the skills you want carried over no matter how many attempts you make. I spent overall several hours getting the 3 most important skills i wanted for Daisoujou carried over, and almost an hour getting both Pierce and Prayer carried over to Metatron. And the former, Pierce is an absolute must for the final boss fight. Just like in Persona 4, the last boss fight is an insane difficulty spike where in your first time playing you have to go back and spend a lot of time fusing demons with the correct abilities to beat it, and you need to have Pierce on your MC. A skill absent from the entire game until the very end. There are also problems in knowing where to go next several times in the game. But thankfully, I used YT guides for this, and guides are something you really need in order to beat it.
The meh: The nihilism can get a bit too much. The story is also really confusing, and some of the dungeons have poor visual design (though I've heard that's far worse in most other games in the series). The game also overstays it's welcome once you take in to account all the time you're gonna be spending in the Amala Labyrinth which like the other late dungeons gets really obtuse at the end parts of it.
I overall liked it (despite the wall of text in 'The bad') due to the strong base game, but it's hard to recommend this to your average gamer. A lot of people will dislike this, and I don't blame them for that.
Sidenote: Everyone knows about the Matador meme. Well, those people never made it to the Trumpeter...