It seems to me they're awful choices of levels to be overused because it's so easy to lose with the powerups just laying around like that . . . it's fine and fun to lose in other levels but when you get crushed in those levels and it's only because you're plugged full of powerup rockets it gets kind've boring.
I'd think that even taking or switching those powerups with something else (Like what happened with the shield in Diamondus Warzone) would even make to make it a more tolerable level. I try to avoid using it to see if I'm skilled or not but if someone else is it's a mess.
It's beside the point though - Personally I like custom levels better because there's piles of noteworthy selections for a quality game. ^_^"


(Rocky)
Stuff is good.