(Copy pasted my comments from the vid with some editing, but I'm 100% sure I have the answers everyone was looking for)
Alright, pretty sure I figured out what's going on, it's not some anti-piracy thing, just a perfect storm of screwups, weird balancing decisions, lack of optimization, and not understanding mechanics. I'm not here to bash on Ross, I just wanted to put this mystery to rest.
It's clear Ross pumped a lot of points into Dexterity on his Hunter, by the time he was halfway through level 3 (Swamp Passage) he had about 121 Dexterity, but not so much into Vitality, by the time he was halfway through the Swamp Passage (and found a machine gun), he only had 21 Vitality (62hp), the Hunter starts with 20 Vitality (60hp), this is very important to keep in mind.
The scaling in this game is super wonky, you simply get so much more value early on investing points into Vitality (+4 hp per point as the Fighter, +2 hp per point as the Hunter) as opposed to wanting to do more damage by dumping all your points into Dex for the Hunter, or Str for the Fighter, or Knowledge for the Mage. I understand you need the stats to wield better weapons, but a dead character does no damage, there's not much point sacrificing so much survivability just to do slightly more damage, your damage is more limited to the damage you deal with your weapon as opposed to amassing stats.
I'm fairly certain I've obtained the 'cursed' 1.11 version of the game that Ross played in the vid, there's framerate issues that I can't seem to resolve on my end though without cranking all the settings down to mush.
I don't know if there's any hidden difficulties, this game has four that you can choose from in the options menu once you've loaded in with your character, Very Easy, Easy, Normal, Hard, the game defaults to Normal.
I was playing the Fighter (who starts off with 80 hp as opposed to the Hunter's 60 hp) on Hard and it wasn't until the initial fights with the werewolves that were a bit of a difficulty spike. They seemed consistent with what Ross shown us, although, by this point, I had invested some points into Vitality, I'm sure I had around 110-120hp and each hit was taking about 25% each, so, 30ish per hit, which is consistent, because his Hunter (with 60 hp) was losing about 50% hp per hit, so, 30ish per hit. 1v1, the Fighter can handle them, 1v2 or 1v3 they become a problem til I get a few more levels and put more points into Vitality, so, luring one at a time helps, a lot. Just to double-check I was playing the same version, I ran through the early game as the Hunter without allocating any stat points, leaving Vitality at 20, putting me at the starting 60 hp, and, lo and behold, each werewolf was chunking me for ~50% hp per hit, forcing me to kite them.
What if I told you, you don't really need potions?
When you meet with the alchemist and access his lab, you're able to teleport back to it freely, and when you talk to him, he will restore all your hp/mana/faith for free, and you can just teleport right back to where you came from, you can cheese pretty hard with this and save a ton of gold you would otherwise spend on potions, because good god, equipment breaks so fast and extra stats from rings can be nice. When you're still weak, the best thing to do is try pulling only one or two enemies at a time, or you'll die real quick.
By the time I was in the dreaded Swamp Passage as the Fighter, I was right around lvl 9 or 10 like Ross, and sitting at 53 base Vitality, 58 total Vitality (232hp, the extra stats from rings definitely help even when pumping Vitality), and of course, the Solidus Vred (Mr. Tough Mob Monster) was by far the most tanky thing up to that point and hit considerably harder, and I was losing about 1/5 to 1/4 of my life per hit (with no armor equipped and all skills disabled), so, if I had to take a guess, that enemy dishes out roughly 45-65ish damage per hit, the variation makes me assume that enemies have damage ranges much like you do, which again was consistent with Ross's experience where sometimes he instantly dies, sometimes he barely survives, because he only had between 60 and 62 max hp at that point, so this means the enemy was sometimes dishing out just enough damage to kill him at full health.
Part of what may also explain the tankyness and damage is the day/night cycle. You'll notice that some enemies are labeled 'Nocturnal', they receive bonus stats at night, they do notably more damage and seem to take a few more hits, he was also still using fairly weak weapons at this point, blame the devs for the bad balance.
Ross completely missed the skills, there's several unexciting but helpful skills, in the Defense tree, there's Prudent Command, you deal less damage but also take less damage, and this helps. In the Offense tree, there's Light of Faith, which reduces the bonuses that Nocturnal enemies get at night. I was just using a Hatchet (2-7 damage), Ross was using one of the early game bows [either 1-3, 1-4, or 1-5 damage), I fought the monster at day, looks like he fought it mostly at night, in my experience Tough Mob Monster goes down in about 28 hits, most weaker enemies around that point could be one-shotted. Even with the Virtue of Care skill (reduces durability damage, starting with 15% reduction), equipment tends to break often, but it helps.
Ross also missed out on the crafting system, it's referred to as Create Item/Item to Transform, the button is in the inventory menu, bottom-right corner, you can combine items as this sort of enchanting system I guess, I assume this is the developer's take on the Horadric Cube(?) just, janky. Armor increases the durability of any item, and then increases the armor rating if it's armor, weapons increase the damage (but reduces any item's durability) if it's a weapon, books/tomes decrease the stat requirements, rings will decrease the total cost of crafting, and then there's some unknown metrics that determines if the item inherits things like stat bonuses, procs, etc, which is shown in the preview, I can't say I've needed it yet but it's interesting.
There's actually two kinds of summons, one is the golem, the other is some flying thing that shoots projectiles, I don't feel it's necessary but the flying one is nice for distracting enemies and chipping away at them for a bit of extra damage.
The rest of the game feeling easier once he was about halfway through the Swamp Passage in Ross's playthrough has to be because of the machine gun, that thing does considerably more damage (8-17?) than the bows and guns (1-5 or 2-4 at most, up to 8 for some of the better, rarer weapons in the early game) he was using, the machine gun also fires in BURSTS as opposed to single shots, meaning he was going from dealing 1-8 damage in single shots to bursts that were averaging 10 or 12 per shot totaling anywhere from 30-50 depending on damage rolls, but the low Vitality was a huge liability all the way through.
Some of the enemies and bosses later on probably don't even get the Nocturnal bonus, but, regardless of that, you get this weird reverse difficulty where once you got a decent amount of health and a nice weapon the game becomes a cakewalk.
