Remember how Knuckles "mysteriously" disappeared? Well, he was simply going after the emerald shards...in outer space! Please let this page load and click the thumbnails for a better quality.

At the lower portion of the level you'll see several meteors placed on different corners. There should be one distinctively placed on a floating platform away from the others. Go to that one and punch it in the direction of the door its facing. The door will break open, revealing a crate. Destroy the crate and a white switch will become available. The switch opens a floor door in the tower before you. Climb up and manage to fall down into the newly opened area. The bottom platform contains Knuckles' Sunglasses upgrade. Put these on to see hidden objects. Once you use them on the platform a spring will appear for you to get out of the upgrade area.

These rockets will take you high into the air, letting you search the upper portion of the stage.

 

Climb around the top areas to find interesting objects. Be sure to destroy those pesky water monsters as well.

 

Sometimes you have to break through floating platforms just incase a shard is in there. Do not stand around in any place long enough or meteor's will crash down into you.

 

Using Mystic Melody on this artifact will create a portal for you to jump through. It'll lead you inside of a rectangular room with another artifact. Play Mystic Melody on that one as well for another portal. Once you go through that portal you'll be placed in another rectangular room with an extra life capsule. Back track your steps to get out. Collect the last emerald in the stage and we're off to Crazy Gadget as Sonic!