Much appreciated, willy... we're thrilled you enjoyed Up All Night!
While we don't know of a way to access the in-game CG files, our artist has them available for viewing in his portfolio. We don't recommend clicking until you've finished the true end to avoid any potential spoilers, but here is the link. If you do end up drawing fan art, we'd love to see it!
Thanks so much for your kind comment and enthusiasm... it means a lot to our small team. If you're up for it, we'd also like to encourage you to leave a review, as this helps immensely with visibility.
Thanks again!