I'm sorry, but this video contains many inaccuracies and misleading statements. I can only verify what I already know well (Looking Glass, Ion Storm, Arkane history), but based on another comment it probably extends to the discussion of V:TM-B and other areas too. Going down the list:

-1:28 This may sound like a minor nitpick, but I don't know why you'd cite the key "two lead designers" behind the Immersive Sim as Ken Levine and Warren Spector. Spector was always a producer and never a designer from Ultima Underworld through System Shock and Deus Ex, and Ken Levine was only a lead designer on System Shock 2 and creative director on Bioshock, having ultimately little to do with Thief (though he is apparently credited with the concept for the stim and response architecture) or indeed any other Immersive Sim titles. Paul Neurath, Doug Church, and Harvey Smith are equally notable.
-3:54 Looking Glass Studios did not "start under the eye of Warren Spector", nor was he the "creator of the first System Shock at Origin Systems", nor was Origin Systems "where Spector and co. created the first Immersive Sim, Ultima Underworld". You correctly reference other parts of the story, but for full clarity: Ned Lerner and Paul Neurath founded Blue Sky Productions in 1990 and later merged with Lerner Research in 1992, together rebranding as Looking Glass Technologies. Blue Sky's first project under Paul Neurath with programmer Doug Church was a real-time dungeon crawler in Underworld, which they showed off at the 1990 June Consumer Electronics Show, impressing Warren Spector and Richard Garriott of Origin Systems who signed on with them for a publishing deal and branded the game as an Ultima spinoff. Spector served as producer for Ultima Underworld I and II as well as System Shock, the latter of which was the brainchild of Paul Neurath, Doug Church, and Austin Grossman. Spector played a crucial role, particularly in ensuring System Shock wasn't cancelled and in offering direction and scope for all three games, but he can't be credited with the design or concept.
-6:08 I wouldn't characterize Immersive Sims primarily by first-person shooter or role-playing elements. Ultima Underworld has minimal FPS elements (unless you count the dodgy slingshots), System Shock has no RPG elements, and Thief features neither of the two (again unless you count the bow shooting). The rest of your definition is well and good (singleplayer, story-driven, freedom to traverse open levels but in a linear plot structure, emergent gameplay) save for the notion of the player character being "nobody of particular importance". I don't see how that could possibly be a foundational aspect, as it's flat wrong for Deus Ex and has nothing to do with the design philosophy overall. That's just a storytelling trope that makes for a compelling player fantasy (see also: Hero's Journey).
-11:29 "However, [System Shock] was also a step backwards in comparison to the Ultima Underworld games as there was no real mouselook." This makes me wonder if you played the Underworld games, since they had a very similar control scheme where you could move and turn with either the keyboard or by clicking and dragging in the view window with the mouse. If anything, System Shock improved upon its predecessor's controls with a simplified frob paradigm (single LMB click to look, double LMB click to interact, no need to select separate look/get/use/talk/fight or use mouse gestures in default mode).
-13:16 "The Dark Engine allowed for more RPG elements in a fully 3D world... [with] the Quake engine being very new at the time and not able to support the RPG elements they wanted to put in Thief" While it's true that the Dark Engine was originally built to power what was originally going to be a 3D RPG in Dark Camelot, Thief had no RPG elements on release and what actually made the engine unique was its object system, stim and response architecture, resource pipeline, and sound propagation and AI systems. These tools enabled designers to create art and game entities without any programming or recompilation of game code, and also powered the emergent gameplay that Immersive Sims are known for.
-11:33 "While it was very fickle, people still use the Dark Engine to this day to make... the entire set of Thief maps called 'The Dark Mod'." The Dark Mod is not a set of Thief maps, nor does it use the Dark Engine. It's actually a total conversion of Doom 3 with the entire purpose of emulating Thief's gameplay and allowing mappers to create levels using idTech 4 (now standalone) instead of the Dark Engine.
-15:36 Ken Levine was not "allowed to form Irrational Games to guide the design of System Shock 2." Irrational Games was formed by former Looking Glass employees hoping to make their own games. Looking Glass pitched a joint project with them, at the time a sci-fi dungeon crawler RPG titled Junction Point, which EA later suggested become System Shock 2.
-23:19 You can easily collect enough lockpicks in the the first few missions of Deus Ex to open all of those lockers in the LaGuardia barracks without needing to "bankrupt your inventory and [not] use a single one" prior (it only takes 1 inventory slot to hold the max of 20 lockpicks, and each locker costs only 1). Also, your LAM placement doesn't need any care to ensure that it has "just enough force to break the locks without damaging the items inside", as item pickups are not affected by damage in Deus Ex and cannot be destroyed.
-43:28 Prey (2006) is not even close to being an Immersive Sim. Don't have much else to say here, other than to note that the game was outsourced to Human Head studios by 3D Realms after being in development hell for 11 years, and they handled much of the actual development.
-46:59 This is a point of major personal disagreement, but I don't know how you can argue that Bioshock simplified the core gameplay of System Shock 2 "without dumbing it down", or state that it was a "fleshed-out, uncompromised Immersive Sim". I can't deny the game's critical or commercial success, but if you examine the game it's transparently evident how much the game has stripped down SS2 into something more palatable for console shooter players. Every character build is a jack and master of all trades with equal access to combat abilities, hacking, weapon modification, and psionic powers. Inventory management is removed wholesale and you're constantly flooded to capacity with all manner of resources. Chemical hunting for research has been replaced with point and click photography for free damage bonuses and perks. Death and failure pose no consequence thanks to generously placed respawn chambers that allow you to carelessly suicide rush every enemy with refilled life and mana. If you read the design documents and postmortems for the game's development it's clear that they oriented the game to appeal to their console audience in the wake of SS2's commercial failings.
-1:10:26 "Of course, Thief 2014 didn't do anywhere near as well as Ubisoft thought it would." Thief 2014 was published by Square Enix, like Eidos Montreal's other games. It does sort of have the Ubisoft cash-in feel to it, though, doesn't it?
-1:17:25 Prey 2017 did not take ten years to be developed. 3D Realms was only involved in the initial concept stage, while Human Head Studios worked on Prey 2 for about 2 years until it was quietly cancelled in 2011, which became public knowledge in 2012. In 2013 it was reported that the Prey 2 development had been handed off to Arkane, and in 2014 the game was formerly canceled. In 2016 it was announced that Arkane's new title would be titled Prey, and that all prior development of Prey 2 had been scrapped. The actual development of Prey 2017 only took about three years, and it was originally pitched as an entirely new System Shock successor.
-1:18:29 Prey 2017 was created on CryEngine, not the Void Engine.

Most of the rest of the video is a fun look at the course of history for Immersive Sim-style games, but as someone intensely interested in the design legacy myself I couldn't abide all of the factual errors, nor your perspective on Bioshock (again, that one's a personal thing). You described this video as something of a Master's thesis for you, so I hope it's not too presumptive of me to state my corrections and criticisms plainly. I appreciate your effort to showcase the games of Looking Glass and those they influenced, and hope that it further broadens the audience for Immersive Sims. With that said, I also hope that people check the sources and some of the mistatements here don't get repeated... and that Bioshock is seen for the pretender that it is (fine fine I'll stop).