Open Sonic is a freeware remake of Sonic the Hedgehog featuring cooperative play where you can control three players simultaneously.
Open Sonic is portable, so no installation is needed. From the introduction screen, you can enter a tutorial to see how everything works. There are also extras, including extra levels and super bosses too! The Options screen allows you to change the resolution, use full screen, smooth graphics and even show your FPS. Finally, you can select from 8 languages and even jump to any stage.
Gameplay is easy to figure out and full screen is recommended. We enjoyed the remake a lot, although we didn't try coop play.
Open Sonic stays true to the original, but with the cooperative twist.