Jane:
Successfully complete the Terk challenges in world 1 to unlock Jane in the water skiing or river surfing challenges.

Porter:
Successfully complete the Terk challenges in world 2 to unlock Porter in the water skiing or river surfing challenges.

Terk the monkey:
Successfully complete the three Terk challenges in the final levels of the game to unlock Terk.

Ground Tumble trick move:
Successfully complete the Terk challenges in world 1 to unlock the Ground Tumble trick move for jungle exploration.

Scarecrow trick move:
Successfully complete the Terk challenges in world 2 to unlock the Scarecrow trick move for the water skiing challenges.

Corkscrew trick move:
Successfully complete the Terk challenges in world 3 to unlock the Corkscrew trick move for the river surfing challenges.