If you have 2 spare power tanks, then use the medusa shield (R2 + 0) to turn everyone to stone. Then, use the Hammer (R2 + 0) to smash the ground. This will destroy the statues, which looks kinda funny
To avoid a giganta when it's charging at you, just before it hits you roll out off the way and you wont get hurt but once you've rolled get back because the giganta may swing it's arms. Hope this helped.