The Earth Dies Screaming is surprisingly well-crafted. It's a bit creaky in the way one might expect a Hammer-esque picture made in the mid-60's to be, but at one hour and three minutes they've definitely cut out the long and excruciating boring part in the middle.
It opens with an amazing lack of expository dialog. The whole thing is really quite tight and "modern" in both the writing and the overall tone. I mean, it's still a bit on the creaky side, but very cool. This movie is in desperate need of a remake (although, to be fair, it has essentially been remade a gazillion times).