How do you get to the challenge stage in sonic generations?

Answer 1

There are numerous Challenge Stages, two different sets for Modern and Classic Sonic, for every main level. So for example, Green Hill has numerous challenges, Chemical Plant has numerous, etc. Challenges are located above the levels, on the platforms, loop-deloops and other areas above the levels. They appear in challenge gates, which are gold and have purple energy in them. An icon appears above each challenge gate, giving you which type of challenge it is.