...because I am seeing screenshots of things that didn't show up when I played. Is there something I need to do? A file I need to add or some such? I bet it's something so obvious that I should have seen it.

Its called "Trap Yuri Garden," but they are simply male crossdressers, not females, which makes it yaoi lol. You cant be lesbian without being a woman. If they were trans it would make sense

When I press play button the white window pops out for a short second and close the game with no error warnings. I've tried sending emails to the publisher got no reply so I'm discussing here.

really the game say trap but all the description and images of the game describe the characters like trans and use female pronouns wasent this supposed to be a vn about traps? why the transgender façade

The earlier titles are very high quality and I think they would benefit a lot from being available on Steam. Josou Kaikyou (女装海峡) and Josou Sanmyaku (女装山脈) are definitely both worth checking out, but unfortunately I can't play them on Steam....