Some spoilers below.
The Good
It is likely that most of the zero issues being released by DC this September will focus on explaining the events that occurred prior to the launch of the 'New 52' last year. Where were these characters then and who they are, are likely questions we'll see answered. The issues are meant to give readers some insight into the identities and back stories of many of these characters.
I will give it up for Robinson; the direction he took with this story really took me by surprise. When I first opened this issue up to read it, I was expecting a lot more backstory revolving around the Trinity since they happened to be the main focus in the first issue of this series. What is their relationship to one another? How did they meet and get together? That first issue left me with a lot of unanswered questions about the relationship between the Wonder Woman, Superman and Batman of Earth 2. So it's no surprise that going into issue zero, I was expecting to have a lot of my questions answered. But this issue isn't about that, and the reader will quickly realize that how these characters got together really isn't that important. It's what led them to that moment and ultimately to their respective deaths in the first issue that is the main focus of Robinson's story.
The issue is told from the perspective of Terry Sloan, also known as Mister Terrific; the smartest man alive. It opens up six years prior, a year before EARTH 2 #1 and reveals Terry's ultimate plan for humanity and for Earth. I think Robinson did a great job depicting Sloan's character in this issue as the ultimate anti-hero -- a man who is willing to do whatever it takes to save the greater part of humanity, knowing well enough that it might mean some heavy casualties. For Sloan, however, a few million casualties can be justified if it means saving the rest of the world from the perils of Steppenwolf. It's an interesting perspective, and not one that the other members of the Trinity necessarily agree with. That's exactly what makes this story interesting.
I think it is good that the main focus is on Sloan, and it will be interesting to see how the character influences Robinson's story in the future.
The Bad
Admittedly, I didn't find this issue to be as good as Robinson's previous issues on this title. This one had a slow start and really heavy expository at the start of the comic, which is fine, it's just not something we've seen a lot of in this series and felt very different from the last four books. It also digresses a lot from the way this book has been written in previous issues since it's told predominantly from the perspective of Terry Sloan. It does pick up a lot, however, as the story begins to unfold.
The Verdict
Although I did feel that there was a slow start to this book, I really wound up enjoying it a lot. It picks up a third of the way through and really sets up an interesting story, giving readers a different perspective. It also allows readers to choose; who is right in this situation? Is Batman being too much of an idealist? It's an interesting addition to the plot.
I wasn't crazy about the art, to be honest. Superman looks very old here and the colors are not as vibrant as we've seen in previous issues of EARTH 2. They look dull and in turn make the art in this issue feel heavy. I didn't find that it matched the tone of the events that took place in this issue very well.
All in all, though, I enjoyed this book and I think the insight it gives readers into the overall plot of the series and the direction Robinson is taking is certainly interesting.