Sonic the Hedgehog Level Creator
From Sonic Retro
The Sonic the Hedgehog Level Creator is a flash Sonic game on the PlaySEGA Website.
Anyone can play created levels, but only VIP Members can create new ones.
Using it's built-in Level Editor, Members can place level chunks and objects, like rings and badniks, into a level grid. The only required object in the editor is the signpost to end the level, anything else is up to the user to make.