Fun premise! Kinda reminds me of Tragedy Looper (a boardgame) and Deathloop (by Arkane Studios).
The prototype seems solid for this stage, great early progress. It's interesting how quickly the grey boxes' behavior becomes readable and also gives the murder this air of mystery ("what you are doing to the green box, you fiend?!")
I had some trouble parsing some of the tile graphics (the brick walls color & contrast-wise seemed like brick flooring at first, particularly since other walls by the start were dark grey), but I'm assuming these are placeholders like the party chatter.
Looking forward to seeing the full game!