Very impressive that you were able to have a story for a week long jam. Mechanics are pretty clever, I think it bugged on the level with multiple rooms, I could not enter the door.
to go to the next level you must find all the proof stuff like papers and the gun. You should hear a check sound when that happens and if you find them all you could move on to the next lvl. Sorry it was hard to make it clear without ui bruh. Thanks