Evolve a Mermaid
In the Final Ocean stage, go to "Hands and Feet" Under
"Evolve" and select "Try to Evolve."
Evolve the body three times to become a mermaid.
Evolve into a Flying Dinosaur
In the Fourth Chapter, after defeating the Mother Prime Frog go
up to the small island next to the
mountain. Go to the top and jump off. You will be able to fly!
Note that if you do this you will lose your current body and start
out with the worst stuff. Despite this minor flaw, being able
to fly is almost crucial to defeating the next few bosses.
Play as a Human
Get to the Mammal stage. Evolve cat jaws and a rabbit body. Go
to "Body" under "Evolve" and
select Ramothecus body. Evolve it twice to be a human.