Having found our Sonic Spinball proto page is missing a load of content, I've been playing the game a bit to get some comparison foundations in place (although spoilers: I won't be getting all the screenshots - it's awkward to work with). Anyway, a feature: if you trap Sonic in these areas, you get the message "How about a ride?" and the camera pans down to show the "ride". In the prototype, it doesn't pan down. However, both the prototype and final game have the same behaviour for the flippers further up, where this message will never make sense (not that it was immediately obvious to begin with - it takes a few seconds to pan and I find most pinball beginners don't trap balls). (see, anyone can become an expert and find undocumented bugs) I've only checked the first revision of the game (the one with the classic Sonic theme... which tbh might be a proto as well but nobody has ever worked that out). There are three other "final" ROMs, and the Game Boy Advance port to check. Bonus points if you get there before me (or indeed finish this job - faffing around in The Machine is not a top priority after a day of work).