In the bad ending of the game, you bomb some volcano looking region of the city with what looks like nukes to kill the dark ones. Got lots of questions about that. Why was that area glowing red? Why were the dark ones thought to be there while during the game they were quite close to human settlements? Or if human settlements are under that red area, doesn’t bombing it also harm the humans? And why exactly was the objective bombing the dark ones while nosalises were shown to be the main threat to humanity? If polis station had accepted helping, would they also bomb the red area? I was under the impression they’d come to Artyom’s Station and protect it manually. Also if those missiles were nukes, won’t that just create more mutants? Are these ever explained in the game or the books?
Sequel expands but doesn’t really change any of that stuff. To OP I would suggest playing the next one, it might answer some of the questions.