Despite it only surviving in small fragments, I believe Emperor Julian's anti-Christian polemic, 'Against the Galilaeans', still brings up some rather valid and interesting criticisms of the Christian religion and its scriptures, both the ones they created and the ones they appropriate from the Jews.
Julian (supposedly, since even these fragments that survive were copied by a Church father in order to refute them, and as such, some of the points may have been edited to make Julian look like a fool) makes some of the following claims:
-Why did the true God, he asks, withhold the knowledge of good and evil from men or express jealousy that men should eat from the tree of life and live forever? Julian explains that the Greeks held that the gods had deified and raised number of human hero-figures to Olympus, and as such, they were much more generous and kind than the "omnibenevolent" Christian God.
-He writes that learned men should find it absurd to believe that the God who created the world, who describes himself as being "jealous", would content to confine himself to caring for a small tribe in Palestine while letting all races besides the Jews worship false gods for thousands of years and not appear to them as well.
Interestingly enough, he also makes fun of Christians for having nothing in common with Jews or the Jewish traditions/theology, which is quite accurate since modern academia holds Christianity to have been Hellenic and pagan in influence while only incorporating surface elements from Judaism. It appears that, even back then, this was very evident.
Shame that we'll never get to see the most convincing of Julian's theses, since the Christcucks simply burned the work and consigned it to oblivion upon finding themselves in a hard position.
One last interesting thing Julian asked: how did the snake learn human speech for it to tempt Eve and Adam?