I find my brain extremely happy when a game provides ample opportunity to make connections, like in Dwarf Fortress, where I watch an event unfold, which can stir my creativity and imagination like nothing else. Writing a story out of it is extremely smooth and easy compared to other sandbox games.
I also find myself in love with immersive sims like Desu Ex and Thief, where level design and exploration take a front seat, every map is like a big playground with verticality and branching paths, where you find secrets and lore hidden around every corner in an atmospheric world.
What is immersion to you?
Immersion is tricky, because it is an incredibly subjective thing. At the end of the day, what immersion means (I think) is that the “veil” separating you from the game is incredibly thin and transparent. Think of it as wearing glasses: if a game is un-immersive the lenses are dirty and scratched. You can still see whatever is in front of you, but you’re constantly aware of the fact that you’re wearing glasses. An immersive game is like wearing perfectly pristine glasses: you forget you’re wearing glasses at all and can just take in what’s in front of you.
An immersive game to me is something that successfully manages to both suspend disbelief and sustain the illusion of a living world, letting you mostly forget that it’s a pre-programmed game you’re interacting with. I always found something like the STALKER games great for this, with their dynamic A-life AI scheduling really selling the whole living world feeling.