Board Thread:General Discussion/@comment-26873653-20151212201934/@comment-679780-20151214214441

LuckysixFroggy wrote: sonic runners only has 3 zone grass zone sky zone and larva zone Windy Hill, Sky Road and Lava Mountain are all zones from Lost Hex. During special events additional zones are added such as when Sonic and friends found bits of Arabian Nights world in Desert Ruins or went on holiday at Tropical Coast.

I don't think they're bound or stuck in Lost Hex, just obligated to frequant it for the sake of Sonic Runners.