The EU and JP manuals are located at https://manuals.sega.com/sega-ages/ They contain nice HD versions of the game logos. But they don't feature any intro to the games themselves, sadly. Can anybody with a JP Switch check what is the address for the JP manuals? Just open any manual and press the "+" button to show the page URL. The https://manuals.sega.com/sega-ages/sonic2 URL isn't accessible yet but I bet they've already uploaded the Sega Ages Sonic 2 manual to the JP servers.
I don't have a JP Switch, but I was able to find the JP manuals. There doesn't seem to be an index page like there is for the English ones, but they are linked to from the Q&A page. The manual URLs are found on the first links under each game. Almost! I guessed the URL, and I got a "Forbidden" error rather than a "Not Found," so it's there, but not available yet: https://manual.sega.jp/switch/segaages_sonic2/
Nice! I hope we get access to the manual before the 20th! There are 3 possible approaches to that, which I've made: Option 1 - Compiling the images into a PDF and have the navigability just by bookmarks. (Works everywhere) Option 2 - Compiling the images into a PDF with the nav bar, with the menu button "☰" opening the bookmarks menu. (Only works on PDF readers) Option 3 - Compiling the images into a PDF with 3 extra pages at the end just for the menu. (Works everywhere) I think Option 1 might do, since it's the easiest to make and the manuals are short but archiving these as webpages would have been the best scenario IMO. Of course the menu could have been applied as a toggleable layer on the PDF using javascript, but then it would only work on select PDF readers, making the effort go to waste if opened on most devices.
Why stop at saving? I've printed some of them out for a personal project and they make for some kick-ass physical manuals. https://twitter.com/TrunerReisar/status/1222528698777292801
