A public beta of my open source fangame,Sonic : Chaos Unleashed.
It's based off this engine:

http://www.yoyogames.com/games/show/79496

Controls:

Sonic and Tails
Arrows : Move
Space : Jump
Down + Space : Spindash

Tails only
Hold space while jumping : Fly

Cheats

Level Select:
On the title screen press shift.
Up-down to select zone,keypad to choose act.

Clock Work and Testlevel1
On the level select screen press A for going to Clock Work (Very early stage) or 0 for Testlevel1

Please give feedback!