First of all- really cool use of the theme. I haven't seen any other "figure out who is the uninvited guest" games in this jam! Not only it's original- it also is the basis for all the gameplay. Really good job on that one!
The presentation- it's ok, but could be better. The characters have totally different style than the backgrounds, so it clashes a bit. The sound is good, but the game is mostly quiet- some background music (or sounds- creaking floors, ticking clocks, wind outside) could add a lot to the atmosphere.
The idea for the game is cool- more murder mystery than horror, but that didn't bother me :) Searching for stuff in the rooms reminded me of old-school point and click games. The dialogue was all right for the most part, but I sometimes felt like it could use a bit of punch-up.
Btw- I failed and everyone died. In the end I solved the music puzzle, and got the message in the tower (attic?), but... it was useless? Or did I miss something? I feel like I need a tiny nudge in the right direction :)
Over all- I liked the game, especially the atmosphere, theme use, and the fact that for a jam game yours had a pretty decent length. I will return to this, to check out the ending :)