Hidden Among Girl

Yuki is a boy enrolled at an all-girls school, for reasons of his own, and his entire situation depends on nobody figuring that out. The premise is basically one long dare: keep the disguise up, keep the questions away, don't get caught.

The setup carries a lot of teasing tension by design, since a school full of girls and one secret boy is going to produce exactly the kind of close calls and awkward staring you'd expect. Played straight but with a wink, it leans on humor as much as nerves.

You move Yuki through the school in sandbox fashion, choosing where to go and who to spend time with while managing how much of himself he lets show. This is the initial release covering one zone, so the school world on offer is a starting slice rather than the whole map, with more presumably meant to open up as the hiding act continues.