It is reasonably good news. Kim wanted the US to drop all sanctions in response for dismantling the publicly disclosed plant to make nuclear weapons materials. They weren't ready to do that. The US were willing to drop all sanctions in response to him completely denuclearizing but he wasn't ready to do that. He has a vision but not the same as the US vision but closer than it was a year ago.
Trump talked about them knowing the country very well (including nuclear facilities that NK has not disclosed). And that he wasn't willing to do enough.
Not a big disagreement. More that they were on the point of a big agreement but it fell through. And as Trump said he is not afraid to walk away from a deal.