The sex scenes... well, the story would still make sense without them, but I think they do flesh out both Noel's and Claire's characters somewhat. It mirror's Noel's view of his relationship to Susan, for that matter - just sex, nothing else. So sure, you could follow it and move some of that stuff off-screen, but I think it would somewhat change the mood of the story.
And as it goes, the engine is an open-source thing that's been maintained for some years here, the skip feature isn't my work. (At least, any further than my decision to not disable it 'cause it's useful. ;-)
The 'bonus' mode is a bit of an inside joke, I'm afraid; an early version I gave to a couple of people who helped me test it had a pastiche of a Problem Sleuth character as the dummy "I haven't drawn this character yet" sprite; there was some demand for the hotelier to remain MSPA-ified, the bonus mode is a concession to that demand. I guess I should really have made it clear in the menu...
Anyway, I'm glad you liked it - thanks for the feedback!