Should Soma be more like Penumbra or The Walking Dead?

[Googolplex]

And when you have to read a guide every few minutes, it completely ruins immersion.

For me it's the contrary. When puzzles are too easy like just picking something up and then set it into a slot and operate a lever or when you just have to mix chemicals by fill them into a glass and operate the burner etc. this totally won't cause any immersion for me.

I want to think, make my own thoughts what I could do as next to came forward. And I always enjoy it to read a manual with secrets that help me solving something. A game has to be "brain-challenging" but without to be unlogical. Everything should be plausible, for example when I can't get on the other side of a room, because there are laser beams or electrical water, then I search for an object I could use as a bridge to get through.

A game is immersing, when there's a lot of stuff that makes you thinking.
Otherwise puzzles just seems like to be "fun-elements" for 12 year olds.

Puzzles doesn't need to be as hard as in Silent Hill for example. But as hard they are in Penumbra is a very good balance. Amnesia was too easy, but I enjoyed the control room with the bridge machinery.

Games with easy puzzles like AAMFP are not bad, but they could be even better when there would be much more "work" for the player "logical work" to get things right by interact with the world. As more interaction, as more a game feels immersing! Even when you can interact with useless things.

For me it's not bad to read an external solution when I stuck. I love it when a game is more intelligent than me. But a perfect way would be when you have to read in-game manuals. But when everytime there's a hidden manual waiting for you to get found, the game feels not plausible. So this should be a design feature with care.