Mini Madness

Stars can only be collected in challenge mode. To play a track in challenge mode, you first have to unlock in via championship. You need the upgrades Gravity 1 and 2 to reach some some of the stars. In training mode, 5 stars are locked behind a force field. You need at least 20 stars to get rid off the force field. Behind the force field you can also find the access key, which is required for the trophies "Attic gift" and "Treasure". Timestamps for each track can be found in the video description.