Croc 2

Croc vs. Dantini boat race: 
Search the waterfall in Sailor Village to find the last colored crystal.

Swap Meet Pete: 
There is a crystal ball when you enter Swap Meet Pete's store.
Croc cannot buy it until he completes all the levels with that tribe.
Return to visit Stinky Pete and you should be able to buy it.

Clockwork Gobbos: 
When you use a Clockwork Gobbo it slows down quite quickly.
There should be a heartpot behind the heart at the end of the area.
You may not get them both at the same time.

Defeating Soveena The Squid: 
The Gobbo in the level gives you TNT.
After you have hit Soveena The Squid twice, some of the crates will be covered with hot liquid metal that hurts Croc and also blows up the TNT box he has.

Secret level: 
In every level there are five hidden colored crystals.
If you get all the crystals in a level, you will get a Golden Gobbo.
Collect all the Golden Gobbos in the first home world to unlock a secret level.