Sonic the Hedgehog ends with a post-credits sequence that sets up a sequel. The movie is set to be a box office hit, which means that more Sonic movies are likely on the way.
A couple of Sonic the Hedgehog movies are a given, but what about a full-fledged Sega Cinematic Universe? Paramount Pictures could snap up a bunch of other Sega licenses, give them their own animated features & TV shows, and build to a team-up movie in a couple of years. The question now is which Sega franchises would be chosen for the theatrical treatment and which characters would be picked to join the Sega All-Stars Initiative?
Golden Axe
A Golden Axe movie feels like a natural fit for the Sega Cinematic Universe. It has a fantasy world with a lot of magical elements, so it could easily fit into the magical portals aspect of Sonic the Hedgehog. Gilius Thunderhead (the dwarf) fits in well as the protagonist and eventual crossover character, as he has been one of the mainstays of the Golden Axe series and has appeared in other crossover games. He could also fit the Thor role in the eventual team and have comical misunderstandings about modern Earth.
Shinobi
The Shinobi games involved a modern-day ninja who fought crooks. The story of the games was never the selling point, rather, it was the awesome side-scrolling/platforming action and disposing of enemies with a barrage of shurikens. The Shinobi mythos is loose enough that you could make a standard ninja movie and use a mysticism connection to link the main character to the rest of the multiverse.
Streets Of Rage
The Streets of Rage series consists of some of the best beat em 'ups of all time and they hold a special place in the heart of all Sega kids, especially if they never had the chance to play Turtles in Time. Treat the main characters as crime-fighting vigilantes (like the Teenage Mutant Ninja Turtles) but strip out some of the sleazier/more violent moments to keep things PG-13, and you have a Streets of Rage movie.
If only one character made it into the Sega All-Stars movie, it would probably be Blaze, with Skate as a close second. Yeah, we know we used Axel in the cover image, but you try finding an SFW image of Blaze on the Internet.
Jet Set Radio
The movies on offer so far have been fairly standard in terms of genre, but that's because they are relying more on name recognition than anything else. The Sega property that would make for the most inventive movie in terms of visuals (with the possible exception of the Nights into Dreams) is the Jet Set Radio series. Jet Set Radio was all about cool kids on roller skates going around town and covering up graffiti with their own tags, while also battling rival gangs and escaping the cops. It had some amazing visuals and a phenomenal soundtrack, making it an excellent choice for an animated feature that could attract the same kind of audience as Spider-Man: Into the Spider-Verse.
In terms of a character for Sega All-Stars, the roster of the Jet Set Radio isn't that well-known, but Beat or Gum would both be suitable choices.
The Team-Up Movie (Sega All-Stars)
The team-up movie in the style of The Avengers will likely use the Sega All-Stars name. The movie needs a bunch of faceless enemies that will be easy for special effects people to animate, which is why the monster hordes from The House of the Dead franchise will fit in nicely. Robotnik could return as the villain, or maybe Shadow the Hedgehog as a way of introducing him to the franchise.
The equivalent to the Infinity Stones could be the Chaos Emeralds, though there could be a number of magic items belonging to each universe that need to be brought together to give someone ultimate power, like the Golden Axe. The House of the Dead zombies are sent to Earth through a portal and the Sega team has to team up to stop them and save the universe.
Post-Credits Scene - It turns out that the person behind the attack on Earth was Lan-Di from Shenmue as part of his plan to find the magic MacGuffins that will help him rule the universe, including the Chaos Emeralds, the Golden Axe and the Dragon & Phoenix mirrors. One of them is probably underwater so that Ecco the Dolphin can have a movie (with a Seaman cameo).
Phase Two - Make movies based on Nights into Dreams, Eternal Champions, Panzer Dragoon, Shenmue, and Clockwork Knight (as the cooky Guardians of the Galaxy obscure franchise pick). Alex Kidd gets a cameo at best.