In the desert level, the primary antagonist is referred to as the "Baron" and he runs an empire seemingly built on oil, which appears to be extremely valued by his regime. Combine this with Damir's statement that Giul's name for the Baron's regime, "Munai-bailer" translates roughly to "oil drillers" and it's likely that this faction originated from a major oil corporation prior to the war, the Baron himself presumably either some high-level executive, if not the former CEO, or a descendant thereof. People who run major oil companies that hold a monopoly on oil are sometimes known as "Oil Barons."
Artyom seems to lack much in the way of swimming skills. On falling into deep water he tends to easily get disoriented, and immediately scrambles to get out, if he isn't killed by something else first. He even nearly drowns at the start of the Taiga level and has to be rescued by Olga. At first, it seems like a strange oversight that Spartans apparently don't know how to swim... until you consider the fact that Spartans are trained to primarily fight inside the Metro and the surrounding area. Inside the Metro, there isn't a lot of water deep enough to swim in, and when it is deep enough it's most likely irradiated, freezing, dirty, full of dangerous mutants, or a combination thereof. Even when fighting on the surface, any water in Moscow that isn't irradiated or containing deadly mutants would still be freezing. Basically, Spartans are probably taught to treat large bodies of water as deadly for the aforementioned reasons, so they only know to swim insofar as a means of getting out of water if they fall in by accident. When Artyom falls into water and immediately climbs out, he's probably habitually assuming the water is dangerous and scrambling to find the quickest way out because of how he was trained in the metro.
He's also loaded down with an enormous amount of gear. It wouldn't matter if he was an expert swimmer, nobody can stay afloat while wearing half their own weight in equipment.
Although the likelihood of prion disease transmission via cannibalism is exaggerated, the fact that the Doctor and the other leaders of Yamantau are still sane while their followers have regressed to talking animals makes some sense. The Doctor apparently evaluates their victims prior to having them murdered, presumably to screen for that kind of thing. He and his inner circle get the “clean” human meat, while the rest of the cannibals eat the ones who don’t pass inspection. It’s also probable that the cannibals have...culled their own numbers whenever they’ve gone too long without bringing in fresh victims, which would increase the likelihood of spreading a prion disease.
At first, the fact that there's a system of radio jammers in place to keep Moscow from making radio contact with other parts of the world seems odd, since past games have had characters mention contacting survivors in St. Petersburgh or in Russia's remaining nuclear subs, but it actually makes a fair bit of sense. The Invisible Watchers were originally planning to flee to the Yamantau bunker, so it's unlikely that they originally planned to use the jammers. It would have taken time to set them up properly, especially if you consider how difficult organizing Hanza as a proxy would have taken. The subs were contacted shortly after the nukes hit. As for St. Petersburgh, it's unlikely that Hanza have maintained the jammers flawlessly in the post war environment with little to speak of in terms of manufacturing infrastructure. There're likely several occasions where at least one went down long enough to communicate with other survivors.
Hanza, the ultra-capitalist faction of the Metro, being the primary enforcers of the will of the Invisible Watchers, makes a lot more sense when you realize that many of the Watchers are likely Russian oligarchs. Naturally, they'd design a society where wealth and status are everything and the wealthy upper class hold all of the power.
