You could try changing the color of the wall and floor to a bit more brownish.

Make it look dirty.


Add some roaches maybe a rat or 2.

Some cracks on the floor and some water puddles.

The light in the room could be coming from a sky light, so rain would fall in the room.

That would cause there to be some moss on the floor.

The skeletons could be different = one could be missing a leg. A few broken ribs.

I would most certainly add some rain, water puddles, moss and cracks on the ground, If I knew how to make things like that look convincing...lol

thanks anyway, the brownish wall and floor looks good