OK i still haven't found any game engines but me and my friends were brainstorming about some ideas so this is what we came up with...

1.

There will be 4 playable characters Sonic, Tails, Knuckles and Amy. Sadly we will not add all of the special power ups for Tails, Knuckles and Amy but stay tuned for that...

2. There are 5 brand new characters to the mix

Classic Builder Sonic.

Modern Builder Sonic

Builder Tails

Builder Knuckles

And lastly Builder Amy who's design isn't finished

And that's all of the updates for now see ya soon bye!