Choices have consequences in this game, and the different endings we are (slowly) working towards, will reflect those choices.
Given the nature of these games, and the structure we are necessarily bound by, choices often result in certain content not being available. Sometimes the difference is minimal and a choice can make something appear at a later time rather than immediately, sometimes the difference is flavour over substance (but in a game that is at least in part roleplaying, such flavour can paint a character's vibe in very different ways). Other times, the choice has radical consequences, both in terms of content accessibility and story. Overall we do notify the player when the latter is the case (I wouldn't but Z is a softie).
Structurally this is not different than the majority of the games here, except maybe with less grinding and no instances of missing content because you didn't show up somewhere at the right time of the day/week.
Whether this makes it a game or not, that's for everybody to determine for themselves.