From what I've heard, some themes will require localization due to region specific stuff (namely the console versions). Personally, I think there is enough of an audience who will gladly take Japanese Saturn even if they live in the US or UK. My guess is the Fantasy Zone and Space Harrier themes were easy to bring over and had the most name recognition of the themes - perhaps they based it on game sales? Anyway, hoping we get more of them. I already have them downloaded and on my randomizer with the Sonic theme.