I don't think anybody "gave up" as such, but I feel like some content exists to make a short game long enough for Steam. Their refund policy ruins short games. Since the beta said it was "50%" of the game, something about double it's length would make sense - The pool & spa followed by the theatre and then the office hell (probably originally with another shadow guy chase in there?) would have made a great full game, I expect, as happens with many games, some of the other stuff was to get it to fit around that, and it's a shame.
Oh yeah, what's up with the shadow guy anyway? In the beta, it was shaping up to be a constant threat that would hunt you throughout the game. But in the final build, it just appeared in the shower room, and made a brief appearance in the mall only to disappear from the game entirely. Such wasted potential.