Well, it'd be pretty easy to introduce a character like Wheatley, or even Atlas & Peabody as someone capable of communication with your main protagonist to break up the introductory area of someone like GlaDOS or Cave Johnson talking either AT them or generically at anybody in X area while they're totally isolated, in order to provide the audience dialogue that's not just coming from above or introspective if it's felt that that's necessary.
Also, while the puzzles are a very interesting part of the game, they're only as much a part of the
storytelling as the commentary they provide in their design psychologically or topically. A lot of the basics that work aside from that from a filmmaking perspective are all of the copious amounts of dark comedy embedded in the sort of science and experimentation that Aperture Science was engaged in.
Conceptually, you're looking at a framework of something like
Mazerunner insofar as you have your main protagonist in a vastly complex contraption of unknown purpose, and they have to figure out as much of, "How, What the fuck, & Why?" as possible and you don't need a huge cast to accomplish that effectively – as the games have shown.
I mean, you can even accomplish that with:
• How'd I get here and what is all this?
• Run tests for this cool portal gun.
• Tests are done & now you die.
• Escape the mad science lab and figure out what I can along the way from the clues left behind.
• Confront the entity at the end.
I legit don't see what all the negativity is about.
X