@ionrayner try a different browser I'm using chrome with no problem at all. Level 21 you have to do it a certain way not sure if it's suppose to be that way or not but the trick is when you knock down the last barrel *do not* let it settle if it settles and stops moving you will only get 3 barrels to blow up but if you open fire when it hits and is still moving it will blow all 4 barrels and kill the monster.
Reviews for "Captain Zorro: Secret Lab"
Rendering never ends... the problem is still here, but nothing about the solution, huh? (Don't tell me to update Flash player, I have the latest version installed, so you need to fix this by yourself.)
You need to fix the levels with the "Stack the barrels on top of the enemy and set them off" mechanism. It doesn't work 90% of the time. The explosion of one barrel launches the others which explode away from the enemy or other barrels. It works eventually, but restarting over and over again, while playing correctly, is very irritating.
Update: Is WORKING on Firefox too unlike what @Theodenrex said.
doesn't work here either, stuck on rendering screen