This is very cool, I don't usually see people drawing 3D scenery from an isometric point of view. I really think you nailed it though! I love the way you drew Sonic's spikes in the more classic style, and the different ring rotations look very well done as well. The shading on the metallic spring is great, as you can tell the roughness apart from the other objects like the box, the ground, etc. and the water is very beautifully done too. Keep it up!