The keys look nice but I think the key color change that is in the game currently helps players know what keys are useful or not. Also the tags on the keys is not necessary since they are identified when picked up.
well for the used keys, i think would be nice to add a Display with the Room's ID, so players don't need to pick up used keys, unsless they want to do it and use it as noise emiter ^^ But i respect and agree with your decission on the keys
