Holy shit, Alex, what a game! When you were asking for a whole bunch of voice actors, I initially thought that was more of a gimmick, like a "I do it because I can" situation, but I underestimated how much it helps with getting you immersed in the story. If it was text only, I might not have enjoyed it as much.
The murder mystery is very good. You really need to go back and forth between all the characters (well except Altmann, rip). There were moments I got stuck. Those moments did have me end up trying things at random, but the eventual solution I found was always one that made sense, I just hadn't thought of asking that person about that particular thing before. I was a bit confused by the ending. I read your head canon. [rot13]V guvax gb fryy gung lbh pbhyq unir rzcunfvmrq zber ba gur snpg gung ur jnf penml, naq gung ur arrqf uryc. V thrff gung vf nyernql fnvq jvgu gur snpg gung ur unf n gurencvfg, ohg fgvyy.[/rot13]
The art looks amazing. The fuzziness around the ghost was a bit distracting at the beginning, but I guess it does add to the ghostiness. Though I'm not sure if that was intentional. Besides the big artwork of the ghosts and the detective, the small artworks of the clues are also really cool. The candle flickering is neat, and even the ouija board had a cool design.
I was a bit confused about the elaborate/keep going. I feel like you would always want to elaborate. At least the first time you are entering that path of dialogue. Other than that I had no issue with any of the mechanics.
I hope your game gets a final rating that it deserves, and is not affected too much by people only playing it for 5 minutes. If someone asks how good and big of a game you can make in 72 hours, I think this will be a great example to show them.