I have not played an adventure game this fun nor engrossing in aaages, if ever. I did each character's story in turn (that is, first Vella's then Shay's), which ultimately felt like the best way to play the game, but of course I say that having experienced it only the way I did. What spurred me to finally play this game after having it sit in my Steam library since last year was watching a Zero Punctuation review of Act 2 and cutting it off right when Yahtzee got to spoilers because I just knew I'd be missing out if I spoiled myself early. I wasn't fast enough to stop the video before I heard just enough to have the game's first reveal spoiled for me (that is, in Vella's story), but that last reveal, right at the chapter close? Holy fucking shit! That made up for it in spades.
Hilariously, the order in which I played the available stories was entirely on accident. At the selection screen, I had intended to choose the boy, but I clicked on the girl first because I figured doing so would tell me a little something about her story and I wanted to survey my choices before committing to one, but when that launched me right into the story instead I just rolled with it, and I had intended from the start to play the two characters' stories one after the other instead of concurrently so I never saw the boy again until I was done with the girl's story.
And because of that, I feel like I experienced the story the best way possible, because all the concepts were introduced to me in a certain order. To give one particular example, a guy from space is introduced near the end of Vella's story and he even mentions Operation Dandelion, which gets mentioned in Shay's. I felt that seeing the guy from space in Vella's story set up the fundamental misdirection of Shay's story far better than if I'd played Shay's story first; I would say that it is largely because I already saw a guy from space, also mentioning Operation Dandelion, that I continued to believe that Shay was actually in space and that Operation Dandelion was real even as more and more of Shay's experience, even the "secret" side with Marek, started to feel like one big lie.
So now I'm worried, what order should I play Act 2 in? I suspect that players are expected to more often click on the left side first, but that would mean playing as Shay twice in a row, and I'm not sure I want that.