Finally! I managed to find all the books, and after that it was just remembering where I left the knife and saw!
This is a REALLY good game! The theme was used in a fun way- I really felt that I was not the part of the crew, and just trying to drop random sentences into other people conversations. I like how the theme affected the gameplay- it's not just "oh there's an uninvited guest"- you really need to behave like a guest at a party!
The graphics also stands out- the pixelated filter and the color palette gives it a retro feel. Using cute animals with the dark subject matter also works nicely, like there's a darkness underneath the cute party.
The sound could maybe use some work. I thought the party sounds were a bit muted.
As for the gameplay- I attempted your game multiple times, and did not get bored or frustrated. First time, I forgot about the time constraint, and lost too much time chatting. Second time, I got caught because I didn't chat enough. Third time I knew what to do, but didn't find all the books in time. Fourth time, I had to take my daughter to her dancing classes, so I didn't finish the game :) Last time- I knew what to do, focused, and rescued the brother!
Some nitpicks (and those are me being picky, the game is great). I'd prefer if all the explanations were in game. Like if you'd place the dinner time, and the hint about books in the text at the start.
Also- the bad ending has a cutscene, but a good one only text. Something like a car driving in the night away from the party would be enough, but still really cool!
Over all- awesome game!