I really like this stuff I love the floor tile.
You just need to like tone down the colours and probably reduce the contrast (I think don't use black) on the floor to make it less noisy.
I also think it would be great if you could do some really plain floor tiles in there like just dirt and some that blend the bones into the dirt to make some variations rather than having every part of the floor so detailed.
Remember its a background so you don't want the player's eye to focus there with warm colours and lots of detail everywhere - less is more.
If I were playing I'd prefer not to notice straight away what the background was as I would be looking for enemies, but then once I had a chance I would be pleasantly disgusted to realise I've been walking on dead bodies...
Yes, you're right on everything, specially about the contrast...
The dirt/bone transition idea is really cool, but that would amount to the same work as wall tiles... I'll make more floor variations but I don't think I'll put that particular idea into practice, sadly just for practical lazyness...
I'll make the floor tiles more brownish and with less contrast, I guess I should go for a "bones protruding out of dirt" approach, but I'll use the same design (it's already been a pain to place all that bones
)
I'm starting to think that I should also remove that "tusk" bone because it's the only one of its kind and looks too pattern-ish.