This is not made by the full Simple Maddness Gaming Studios, this is made by one member, who calls himself Silver Team.
The Incomplete:
No Sound
No Rings

The Complete:
Sprites
Backgrounds
Enimies

The Game info:

Sonic has been trapped on the planet Dupelon, in a parallel universe by Dr. Ivo Robotnik (Eggman) whilst on this parallel planet, Sonic discovers that there are versions of zones he has visited before (Green Hill Zone, Marble Zone ect.) and some new zones somehow thrown in! On this new planet Sonic has discovered the abilty to shoot lasers by spinning! He needs to get home, But how...? Only you can find out!

Move Left/Right: Left/Right Arrow Keys
Jump: Ctrl
Constant Jump: Alt (Do not hold down)
High Constant Jump: Alt (Do not hold down) + Ctrl
Fire Lasers: Space

Silver Team used a Commander Keen Game engine.

Fun Stuff