First of all, let me say that this game is one of the few that I won't forget soon.
Its humorous style was unexpected for a game with such deep thinking in it, but it was a welcome addition to all the arguing and philosophy.
The story was fun and the dialogue exceptionally well-written, however I cannot give it 5 stars for one basic reason that others have pointed out as well: the game is fairly limited.
Now, of course this is not an argument simulator, you need to ask specific questions to have specific answers, but in some parts, especially Kant, a challenge option makes perfect logical sense but is dismissed like all the others for no good reason.
Allow me to make an example: when Kant talks about the rules that must be followed at all times, you could use the "Intentionalism" challenge: to be moral you must always follow certain rules, but what if your intention was to follow them but then you couldn't, for outside reasons?
Are you moral for having a good intention or immoral for not following the absolute rule?
Basically, my point is that some of the challenges should be removed over time to avoid confusion, since you're never going to use the same one twice until the Arbiter, but there's no way to know this until you painstakingly test it. Speaking of testing, some other stuff could be removed as well, like asking for more information on points you already made.
Those are actually valid points in a few instances, but for the rest of the game they are completely useless: however, you are forced to try them anyway to see if that is the one that will be different from the others.
Yes, all this would make the game much easier, but the difficulty of the game should be figuring out the answer in a logical way, not clicking everything until you get it right.
So, to summarize, if an answer makes sense but is not the right one you should remove it since it's frustrating to think you've made a logical conclusion but have the characters make fun of you for no good reason when it's the game's fault, not yours.
Oh, and the game will sometimes bug out and restart, which is incredibly frustrating as this happened to me at the very last question of the Arbiter, so I had to start the entire thing over.
I would certainly love to see a second game like this, all of the parties involved in it are really talented and should keep doing what they are doing.