Tip for Igloo challenge: Get the Anti BF and kill everyone except the last guy. Dash into him to put him at the edge, and dash into every other bullet he fires.
Tip for Border: Prioritize gunners first, the rest are easy to dodge. If you have uber critical, Critter and a decent leveled shotgun, it'll be easy. Use Slowmo if you have to.
I might have given a 5 if the levels didn't take so long to complete.
Then again, I've forgot that you MOVE weapons on blue goo and it pretty much skews everything.