wallace and gromit in project zoo
that bit is hard but i duno i forgot soz 
darn
are you on about this bit.
this might help on all your game difficultys.
http://uk.faqs.ign.com/articles/493/493690p1.html
this might help a peice from the link above.
8.2.3 Boss 2: Gyrocopter chase
------------------------------
This is more an obstacle course that a boss. Navigate the
the gyrocopter through a narrow passage trying to avoid the walls.
The attack button will fire porridge and any enemies that might be
in your way. Try to pick up turbo on the way, the jump button fire
the turbo for a burst of speed. You'll need to use the turbo at
the end to get through the blast doors just after some jets of fire
before they close. This can be frustrating but you should get
through after a few attempts.
8.3 World 3: Volcano
--------------------
8.3.1 Area 1
------------
HINT: Rescue the Gorilla baby over volcanic pit.
-----------------------------------------------
This level starts in a trash compactor with a 30 second count down
timer. Jump up on some boxes and on to a ledge. Flip the switch
to stop the compactor. You'll get the fourth weapon, the fire
extinguisher during the cutscene.
After the cutscene Gromit is standing on a rock in a lava pool.
Jump along the rocks using the extinguisher on the flames. Gum up
the machine with the porridge gun and extinguish the flames that
shoot up from the fallen pipe. Jump on to the machine and down to
the rocks past it. Destroy the penguin and jump up to rocks on to
a small platform. When you're on the small platform you can perform
a backflip (start moving in one direction, reverse and jump) to get
on the platform on top of the pole. This platform will sink and
the platform under the opening in the outside wall will rise. Once
that platform has stopped rising drop down onto it, and quickly
perform another backflip to get through the opening.
Oh, that bit's hard! 
Me too.
VERY CONFUSING!!!!!!