Pseudoregalia creates the effect of a dream-like reality very effectively. The ps1-esque graphics are the main contributor to this, fog, character framerate, resolution and low polygonal design make it all feel "ethereal". This works greatly in the games' service, as a metroidvania.
The feeling of getting lost in this world is unmathced by any others, spending time mentally keeping track of all the walls of the great castle, slowly uncovering the full extent of what your moveset can do it, its unmatched by anything else i've experienced.
Which means you collect items which you can use for progression, .