This video shows Luigi's Mansion beta footage. The ending on this really creeped me out.
Comparisons There is a Luigi scream in this video that I don't remember hearing in the final product.
The Boo Radar's beep is different. In fact, I think it was a radar for all the ghosts in general, not just the Boos.
The Gameboy Horror is Different (you can see its screen, and there's some sort of clock on it.)
The health meter is differnt. (instead of the number in the heart, there's a fraction by the heart. It says how much health you have out of 100)
There are a few white ghost mice (the mice in the final product were blue, pinkish, and gold). As a matter of fact, I think I saw some white ghosts in general.
The ghosts don't have as amusing a sequence when the flashlight stuns them
Around 1:17, there's a meter in the bottom center that looks very similar to the one for the Poltergust's Fire, Water, and Ice powers. What do you think this meter was for?
The coins spin around without falling flat on the ground.