Well even though it won't make any difference if you destroy them all (force field image disappears, but it stays there no matter what and you can't pass through), I've figured out a relatively easy way to get rid of those hard to destroy bubbles...I've never really had a problem destroying any but the top left, that proved invincible despite taking out every single other one like clockwork...anyhow, I was just thinking, surely there's a blast radius large enough to overlap through it... and it struck me that a Shofixti blaze of glory explosion might do the trick. I tried it out, and after a couple unsuccessful attempts to maneuver close enough, I was able to dodge the green ball + fireball (only 1 of each at the beginning of the battle, if it was all 3 fireballs and 4 green balls, I doubt I'd have been able to do it), sure enough, 1 explosion wiped the top left bubble out. I was able to get rid of the other ones w/ utwig juggers (+ patience) and pkunk furies. Well I doubt the next version will have this same bug, but hey if so, here's a simple workaround.