Update 2024-06-14: Fixed with the new file uploaded today.
The U0.1.5 Linux build download doesn't seem to include the adult content, and caps at night 5. It does include the new plush.
(The demo Linux version was probably uploaded as the paid download version by mistake; they have the same zip size)
As a fallback for now, the Windows build (run through Wine) works for the gallery, though the progress will not carry over to the Linux version.
Will wait on a future update for the Linux version. Seems like a lot is in the works in any case.