To access these stages , the player must find one of Sonic 's friends ( either Tails or Knuckles the Echidna ) hidden within a level .
To access these stages , the player stand next to them with at least 50 rings collected .
To access these stages , the player must find one of Sonic 's friends ( either Tails or Knuckles the Echidna ) hidden within a level , and stand next to them with at least 50 rings collected .