Level 99 seems at first to need a Potion or two to get the needed Points for 1 Star. But of you are willing to sacrifice a Heart or maybe two, there will be a nice reward, when you hit that 2 Star and haven’t spent any Potions on level 99. :)
You don’t need Potions at all at lvl 99, if you have unlocked the Rainbow Bubble that will help you score better, since you can generate some tasty green spiders using it. Remember that you can stop the Bombs by placing Bubbles all around it again.
It is quite tricky aiming you are going top do at lvl 99. Watch out for the timing on when you drop the big diamond, because you really want some spiders under it when it falls.