Board Thread:Questions and Answers/@comment-32948273-20160129174948/@comment-5956954-20160209133516

Gotta agree with cookiesandchicken here.

It is pretty much implied as well that the room where you see overworld kid asriel is almost completely empty as well, possibly showing the damage they done to the world.

"The world is ending."

Also, i don't think flowey himself destroyed the barrier. Frisks soul was fighting flowey which had 6 souls. Combining the power of all the souls, and the super intense battle that ensured, it is possible that the intensity weakened the barrier while they were fighting, and after the fight, pretty much exhausted the barrier and gave frisk the exit, while still being there to keep the monsters underground. Its like, weaken, then strike, where it reauires less or the same power to make the same or greater effect, such as frisk leaving the underground with only their soul.

But that is just a theory, and is probably not canon.