For as you may recall, thus revealing your age and unfaded memory, Zap Comix was the sometimes "underground" publication which made R. Crumb famous and was frequently busted for violation of community obscenity standards. According to Mark James Estren's A history of underground comics, lawsuits drove Zap "underground" in 1969.
Zap did not reemerge until 1973, when the U.S. Supreme Court clarified matters somewhat in its favor. Which brings us to the provocations of the lawsuits - graphic portrayal of explicit sex and drug use - all summarized by Ben Myers in the Guardian.
R. Crumb did draw his own version of God in the Zap Comix days, as the Washington Post explains in an On Faith column:
Digression: Actually, God appeared 40 years ago in a Crumb comic-book story called "Dirty Dog." Back then, he was a malevolently gleeful bunny operating a television camera and saying, "Hi! I'm God! Let's get going!" Beneath him, Dirty Dog skulks down a city street accompanied by blues lyrics -- "Rather drink muddy water, Lord, sleep in a hollow log, than to be up here in New York treated like a dirty dog." Poor DD ends up slavering over magazines in a porn store, and the bunny is long gone.
Crumb's Genesis version owes more to William Blake's etching with watercolor Ancient of Days than to the days of Zap Comix. Now the subject of a Hammer Museum show, R. Crumb's approach to Genesis is deliberately straightforward, as he explains in his introduction:
If my visual, literal interpretation of the Book of Genesis offends or outrages some readers, which seems inevitable considering that the text is revered by many people, all I can say in my defense is that I approached this as a straight illustration job, with no intention to ridicule or make visual jokes.
As every reviewer we've read has noted, there is a sense in which the material does fit his style. Not that no one will be offended. In these days of Halloween Bible burning celebrations (all but the King James version go on the Amazing Grace Baptist Church pyre in Canton, N.C.), there is plenty of fuel for pyrotechnical sermons still left in the work of R. Crumb.
The Sydney Morning Herald tells us there is anger in the United Kingdom. One commenter admits he hasn't seen the book and the others make very general statements of disapproval.
Perhaps they're angry because as Susan Jane Gilman says for NPR, the work is "humanizing. Crumb takes the sacred and makes it more accessible, more down-to-earth, less idealized. And this may be a blessing, or it may be subversion itself."