I have felt for some years now Astebreed could be a spinoff of Zone of the Enders. Astebreed is a hyrbid of a Shmup and Hack N Slash that allternates from a vertical shooter to a side scrolling to a behind the back game.   How the game starts and something about the story feels like it could be a ZOE side game.

Staying on the ZOE theme. Daemon X Machine feels like a cross between Armored Core and ZOE which likely was the intent.

Dragon's Crown could easiy be a sequel to te Capcom Dungeons & Dagon's Arcade games and that was the intent by some former staff of those games. BONUS Earth's Dawn (Wars) feels like Gears of War setting meets Vanillaware art and gameplay but is form a different dev.

God Hand could easily be a Fist of the North Star game.

Every Souls game and Elden Ring desperatley want to be a Berserk game.

Lastly for now The Journey Down point and click games have a very Grimfandango feel/atmospher to them.

Sackboy desperately wants to be mario 3d world.

Lost Odyssey could (and should) have been part of the Final Fantasy series.

The creator Sakaguchi, He birth the IP and let Microsoft have it. It's most people favorite exclusive JRPG from Microsoft would be cool if this was on Nintendo Switch. Thumbs up Ka pi96.

"Every Souls game and Elden Ring desperately want to be a Berserk game."

Well, I mean, Miyazaki has been very open in the past about being heavily inspired by Berserk..

Would've been funny if Capcom published the heavily inspired from the early Resident Evil games, Tormented Souls and marketed it as an old-school spin-off

Clockwork could just be a sequel or reboot of Bioshock Infinite from the trailer.

I don't know much about Splatoon, other than playing some of the first game. The gameplay was going to be a Mario spin-off. It almost feels like it was going to be an inverse of Super Mario Sunshine. So, there we go.

When I first saw NyxQuest for the WiiWare, I thought it was some sort of spinoff to Kid Icarus.

The Mario + Rabbids games feel like spin-offs of Banjo-Kazooie (helped by the fact that all three share a composer). Jet Force Gemini seems to have found a successor in Earth Defense Force (any of them, they're all third person shooters where you kill space ants).