Personally, I really like the atmosphere even without any voice acting. The writing, art and audio design are already great and I feel like adding full or partial voice acting on a lower budget might run the risk of ending up with mediocre voice acting - which usually does more harm than good, in my opinion.
That being said, maybe it would be doable to add some unintelligible noises to... erm... flesh out the environment on the audio side? Like, have friendly NPCs do a little harumph or something when you initiate a conversation, have humanoid enemies yell angrily when they attack you (and do a death rattle when you kill them)...
I think some older games (Baldur's Gate / Neverwinter Nights, IIRC) also just played random, unintelligible noises of people talking or yelling in the distance as an ambiance track, to suggest that NPCs just off-screen are interacting with each other in inhabited areas.
Post edited August 07, 2021 by Exsurgent