I LOVED the first issue! Now THIS is what I was expecting from Hickman when he left the indies to come to Marvel.
I also enjoyed the art by Dustin Weaver (although I admit I bought the painted cover by Parel instead) despite some of the rather... puzzling complaints on that other thread Medieval Guy refers to (none more ridiculous than the one from the guy who says the story sounds "too English" for him, whatever the heck THAT'S supposed to mean)
Of course, using famous characters from history like Leonardo and Galileo and Isaac Newton for a "secret conspiracy" (be it Rosicrucians or the Illuminati or Dan Brown) is hardly new, but Hickman shows he knows what he's doing in only one issue already. The story is a lot of fun and filled with awe-inspiring scenes, like the Chinese guy facing a Celestial WOMAN (how cool was that? ) or that first view of the Immortal City, which reminded me a lot, probably intentionally, about that story by Borges (I'm sure someone here will think it "too English" to make a Borges reference in a comic book, or that the perspective angles on that panel are all wrong. Sigh)
It's odd the Leonardo story is set during 1495. I would've thought it easier to set a decade before when Leonardo was in Milan, but I trust Hickman knows what he's doing. (And that scene with Galactus walking the skies over Florence is amazing)
In short, highly HIGHLY recommended.