You don't actually need the sound. You use your mouse to check. The top of the eye of the redghost should match the eye of the black ghost. So hold your mouse where the black ghosts eye is, try and memorize where your mouse was, put your finger there, whatever and match the red ghost to it. Allow your mouse to be in the same spot when the sound wave goes around for both the black and red ghost, just to double check. Do this for all the ghosts, I completed it quite fast doing this method. If this method is helpful, bring it up to the top, just so other's can see it.
Great games - some annoying bugs where you can jump into the bottom of certain platforms, had to refresh. Overall great game. (And there's a level in the jungle that you can farm for so many levels, I think I did 10 - 20 in like 2 minutes, it gives off 34exp for completing, plus those slime things that give 3 each PLUS those droppers)
A good strategy is mines.. fill your screen with mines, and make sure you upgrade your turtle valve. Once you have about 5 or so mines, and you are blowing your screen clear of turtles, add some buzz saws, but add turrets as the turtle shells may not go down fast and could cost you some precious time. If executed correctly, this strategy works perfect.
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