Potions: Extra bubbles, rainbow and ceiling holes
Clear the bubbles directly under the long skull line on the right hand side, then clear the left side to bank shots off that side to unlock the lock. Clear the bubbles under the skulls before you unlock the lock.
Bank shots off left side to right side above skulls to stop infection. Then unlock the lock on left side. Bank shots off the left side to shoot up above the infection to make it drop.
If you get to the top and have plenty of bubbles left, increase green spiders before the drop.