I love a murder mystery, I think you've got the building blocks of a good game.
Its not obvious that the rectangles are keys. On my second play through I did try to go directly into the house instead of exploring around the outside and wasn't able to because I didn't have the key, but the first time I'd picked up all the keys before I got to the doors.
There's very little to search downstairs and nothing in the first room, I think for the player its nice to give them an easy win early on - and introduce the searching mechanic, although I see that the game is random. Both times I played, most of the clues were in the bedroom.
The first time I was killed by the cable guy, with a rock in the kitchen (although I note that the house doesn't have a kitchen haha)
The second time I was killed in the bedroom, with a fireplace poker, by a ninja!
For me, I thought the look speed was a little fast