I did the "are you entertained" in the level with the "sasquash".
I got it unplaned and later noticed what i did.
http://imageshack.us/photo/my-images/69/areyounotentertained.jpg/
On the right bottom where the spiders spawns (near the gate) build an artillery (just lvl 3). He kills any ground unit.
Near the sasquash build a soldiers/paladin and command they above to the road near to the sasquash to block some enemys (in range to the barbarians).
Near the artillery put a weak lvl 1/2/3 archer (cant remember), just to hit the flying units, but not to kill it, thats the task for the barbarians.
Build the barbarians barracks near by the paladin barracks and full upgrade it and command it to the bottom road near the sasquash.
Now this is how it works. All big enemys are blocked for a while by the paladins, while the throwing axe sometimes kills the units. Small enemys killed by the artillery.
If someone pass, the barbarians do enough damage to kill it and dont die.
And by the way, thats it, all flying enemys killed by the barbarians, while paladins and artillery blocks and kills ground units.
I hope, you understand it a bit.