Should have built an elevator, instead.
It can't really be a good thing that, more than once during my brief attempt at The 39 Steps, I considered reading the book instead.*
My experiences in the "visual novel" genre have been pretty diverse, ranging from a detective-style literary investigation, to riddle- and puzzle-filled interactive adventures, to a meta-narrative that plays with the idea of a story itself. But The 39 Steps isn't much like any of those -- disappointingly, it's most like ... a book. The story is totally linear, with no semblance of choice, except in the very minor cases of choosing to read a supplemental note or skip it. And there isn't any significant interactivity to it, either; the closest it comes to being a "game" is in some poorly-advised gesture-based quick-time-events.
Even as a click-through movie (which I guess would make it a slideshow), The 39 Steps is of an overall low quality. Most scenes aren't animated at all, or only in the barest of senses. The visual styles are all over the place, haphazardly switching between painted realism, pop art, and ... mock-propagandistic motion comic? And the voice acting is bad. Not the worst I've ever heard, but just bad; especially in a scene I played where two characters spoke to one another, but their voice actors didn't seem to be aware of each other at all.
There are some slightly-redeeming qualities here, such as the occasionally immersive environments and sound effects; an early point in the story really evoked the sense of walking along a rainy London street. But these victories are too inconsistent and infrequent to save the whole experience.
The plot seems like it might be interesting on its own, but not worth slogging through this slow, uninspired presentation for.
(* I did end up reading the Wikipedia summary, although it unfortunately isn't very well-written.)
Progress: Finished the first four "events" (chapters).