Sonic's universe is thrown into chaos when a mysterious new power comes into force, creating 'time holes' which take Sonic and his friends back in time. Whilst there, Sonic runs into some very familiar characters from his past including a younger version of himself! Now they must team up to defeat their enemies, save their friends, and find out who is behind this diabolical deed. Play as both Classic Sonic and Modern Sonic in the ultimate Sonic experience. Master the moves of each character as they race through each environment on their own specially designed track. Iconic environments from gaming history come to life in beautiful HD for the ultimate Sonic adventure, each revisited, recreated and re-imagined with stunning results. Play some of your gaming's most iconic environments in a whole new way with famous Sonic stages presented in stunning new stereoscopic 3D. Once you complete each level and 'free' Sonic's captured friends, you'll get to go back and take on more challenges with them at your side. Take on some of the most notorious characters from Sonic's past as you fight for ultimate supremacy. Master Classic Sonics famous spin-dash attack and utilise Modern Sonic 's 'Sonic Boost' as you complete the all new tracks.