User blog comment:SigmaAlphaThree/Sonic Dash/@comment-15225862-20140130020512/@comment-24216186-20140130020703

It's kind of like Temple Run, if you've played that...

and yes, it's totally free, and you can choose to play as just Sonic. But they have characters like Tails, Knuckles, Amy, Blaze... but you're not required to play as them.