It's nothing like Sonic 3D Blast or Marble Madness, but it's not supposed to be. Sonic Labyrinth involves a slower, happier Sonic spinning his way to a better life by...you know, finding keys and stuff ("I know, I'll scatter keys throughout my arena of death and then attack with but a fraction of my full ability, just to screw with him a little! Ha ha ha! Ha ha ha ha ha!"). It has little in common with any other Sonic game in terms of gameplay or design, but it's a great game overall and casting the spiny one as the star was just a nice bonus.