I'll start with: I know this game was made in a month, however, I do think that if you're going to make a game with serious and dark topics that need researched then maybe consider... not doing it in one month. I get that it's for a game jam, and that it's also good practice to see what you can improve on, however it's just in poor taste considering how rushed, and poorly written this is. There's 8 authors contributing to this game and it still turns out like this? You probably should've chosen an easier premise for a game with an extremely short deadline. I've seen the twitter posts too, and I think your idea would've been very interesting if you decided to make this a longer project and took your time on it. This game is an example of; right idea, wrong execution.
The game has a bubbly and fun vibe the entire time right UNTIL the end which makes the endings feel extremely random. If this game was longer, you could've gone into more detail and attention on Ryuk's role earlier on in the story, because if you get an ending like the suicide one then you will not know about ryuk's involvement. You could've also made the days nearing the end a lot more eerie or jarring to get a smoother transition to the end.
If the creator intends to keep the game up then i can only hope they remake it without a deadline and take all the criticism into consideration.