Update: Potentially lending some more weight to the rumour, French retailer Sogamely has "SONIC COLORS ULTIMATE - LIMITED EDITION SWITCH" listed for 34,99€, with PlayStation 4 and Xbox One product pages also live (thanks, Nintendo Everything). It's not clear if this listing went live before or after the game was spotted in IKSample's list of credits.
Original Story (Fri 9th Apr, 2021 18:55 BST): German production company IKSample has a long a storied history providing localisation services across the mediums of film, television and video games (as you can see for yourself by perusing the credits on the company's website). However, one or two very interesting video game projects appear on its projects page, and an eagle-eyed individual has spotted a remaster of none other than Sonic Colors just sitting there on the internet.
As highlighted by @OnTheDownLoTho in the tweet below, there it is listed in the company's 2020 credits section, just there for all to see:
Looking around the rest of the website, you'll also spot some rather confusingly-named games — potentially just project code names if the 'U-King – Zelda' from 2017 is anything to go by (which was supposedly Breath of the Wild's development name). Alan Wake, rumoured to be returning in Remedy's next game, gets a mention along with Final Fantasy IV.
Further investigation might cause you to run for the salt and grab yourself a pinch — you'll find the game mentioned again on the company's About page, although it has key art from Sonic Boom rather than Colors. At this point it's impossible to tell if this is simply a random mistake or if someone's let something slip. Still, of all the 3D Sonics from the past twenty years, Sonic Colors (or Colours, if you prefer) is up there with the best of them.
Would you be interested in seeing a Sonic Colors Remaster? Let us know your thoughts on this rumour below.