I thought about it a bit. Since the sound is really the only thing that defines the environment you're in, I think it would be great to add more audio feedback from movements and the environment.
Say whenever you are closing in to a wall (not ram into it), the sound from your footsteps would indicate that. Same with room size - be it an echo of some sorts or whatever.
It would give you a better understanding about your environment, and what to expect from it.
Also, it would probably be a good idea to note how many tiles away you start hearing sounds from fire/chemicals.
I felt it was quite hard to know whether you are surrounded by obstacles, if you are in front of one. The sound from in front of you kills the one that's to your side.