Toward the beginning of James Pond 2, you'll find a group of collectibles laid out as such:

Not too exciting, right?

But!

If you collect them in this order:

Cake
Hammer
Earth
Apple
Tap (at least, I'm pretty sure it's a Tap... like a spigot)

(the first letters of which conveniently spells out the word 'CHEAT'), you become invincible... for several minutes, in fact. I was able to clear out two whole areas and part of a third before it wore off. Just don't get too complacent, it will wear off without much of a warning.