MysterD: So, here's another thing - let's look at Bloodlines (i.e. my favorite game of all time).
I love that game to death (pun...maybe intended here?).
Anyways, to me - this is one of those RPG/FPS/TPA hybrids.
TPA = third-person action - since melee switches automatically to third-person action game w/ the camera behind you. FPS = First Person Shooter, since shooting in first-person which is why I also put the FPS tag in there.
So, I think my question is...is this also an
"immersive sim"?
To me, it felt more Deus Ex-like and "immersive sim" than even say Deus Ex: Invisible War. IW dumbed-down a lot there - while the other main Deus Ex games (Deus Ex 1, DE: HR, and DE:MD) really did NOT.
There are often numerous classes and ways to play the game and finish quests in Bloodlines - similar to a Dishonored or Deus Ex. And if you're say Nosferatu and/or use a character focused on stealth - you can approach areas, entrances, and whatnot...a bit differently than other normal characters with straight-up combat (whether you go w/ say shooting, melee, or say combos of both.
To be honest, I didn't even know earlier about such term as immersive sim. From what I understand though (reading the definition and typology), it's rather considered as sub-type for action games, which would suggest, more or less, that the main "core" of Bloodlines is (probably?) action game.
Kinda tricky example (Bloodlines), and for good reasons (you've listed a lot of them).
My general though is, that for better understanding I should try to find out, what is the "basic" piece of paper, and what are "add-ons" which are glued to the paper. Of course this approach will work well only if we've got some concrete form, while content can be easily "mixed" (e.g. mentioned Bloodlines - it has a form of first/third person action game, while content is a mix of action game (with many sub-genres, like stealth game, shooter etc), cRPG, somehow even adventure game etc.
And I know this approach may sound a bit technical, especially for someone who would prefer to give more significance to content than form. On the other hand - I believe that some sort of typology and definitions should be clear and (as much as possible) unambiguous, otherwise we're literally unable to discuss this matter ("this is fluent, everyone has opinion, none of them is better than other").
A lot of games that have qualified and been referred to as "immersive sim" include - Thief 1 + 2; Deus Ex series; Dishonored series; Prey 2017; and System Shock series.
Also, Weird West is another one that is up-and-coming - but isn't doing it from a usual perspective. It's using the isometric viewpoint.
