Porter
Finish the Terk challenges in world 2 to have Porter in the water skiing or river surfing challenges available.

Terk the monkey
Finish the three Terk challenges in the final levels of the game to have Terk available.

Corkscrew trick move
Finish the Terk challenges in world 3 to have the Corkscrew trick move for the river surfing challenges available.

Hidden FMV sequence
In order to get see a hidden FMV sequence about Tarzan, gather all 75 Film Reels.

Ground Tumble trick move
Finish the Terk challenges in world 1 to have the Ground Tumble trick move for jungle exploration available.

Jane
Finish the Terk challenges in world 1 to havek Jane in the water skiing or river surfing challenges available.

Scarecrow trick move
Finish the Terk challenges in world 2 to have the Scarecrow trick move for the water skiing challenges available.