Yeah you have to ****ing work for this good ending, especially on your first try. One, you gotta go against every emotion you're feeling and not push this crazy idiot into the TV.
Two, even if you think something's off, you gotta answer to Yosuke arguing with you six times before you get to progress with the good ending. Like you really gotta believe in yourself for this ****.
Three, you really gotta intuitively suspect who the murderer is. Like you said, the game doesn't just lay it out for you. I guess you could just reload your save and go through the list for each suspect, but who are we kidding. The real murderer was obviously Nanako.
Four, the entire plot was about the serial killing so expecting the player to go and God Hunt is pretty ballsy. Like damn. You really gotta think if you don't wanna use a guide.
But yeah, it's a pretty good finale even if you knew who dun it. Plus Nanako "dying" and Dojima being sad beforehand was the saddest thing ever and that's when it clicked with me that I love the cast.
I also like how Adachi is just a bumbling idiot. Like Goro is a mastermind chess player with extreme athleticism and the will power of adult politicians. Meanwhile, Adachi's just some bored and lazy asshole who got lucky and has no apparent talents nor drive to improve his situation. It surprisingly realistic for a murder motivation. You know, compare to ******* child conspiracy plot developed by a teenager.