Bluebee
Finish all 10 combo stages and the last stage in challenge mode.

Aimee
Finish the bowl ramp in ramp mode.

Clarice
Finish all 10 Gawoo attack stages and the last stage in challenge mode.

King Gawoo
Finish street mode under the normal difficulty setting, then beat King Gawoo in street mode (flip side) under the normal difficulty setting.

Grandma B
Finish the normal ramps.

Mr. Honda
Finish all 10 trick stages and the last stage in challenge mode.