- Making people naked. Clearly the author viewed nudity as fundamentally wrong, but God created Adam and Eve naked and placed them naked in the garden, without the knowledge that they should dress themselves. That's straight-out evil from the author's viewpoint.
- Keeping the knowledge of good and evil from Adam and Eve. This not only kept them from getting dressed, but also from being able to do good or avoid evil, at least intentionally. Aside from being generally sneaky, I think this is evil because it prevented good and encouraged evil.
- Lying to them. God claimed the fruit of the tree of knowledge was poisonous, when he knew it was not.
- Punishing them and the serpent unjustly. It was unjust because (1) they didn't know right from wrong when they ate and (2) because he never even said it was wrong to eat, just that they shouldn't because it was dangerous, which wasn't even true. Not to mention (3) that eating was in fact good because it is good to know right from wrong. And the serpent didn't even eat, he just told them the truth. So punishing them was unfair. And just to guarantee that it was unjust, God also punished their children, which makes no sense.
- Killing some animals for no reason but to make coats for the people wearing aprons. It's not entirely clear that God killed the animals; perhaps they just happened to die conveniently. Anyway, the animals had done nothing to deserve becoming clothing.
- Throwing the people out of the garden just to preserve God's power. God was afraid that if they ate from the tree of life and lived forever it would somehow be bad for him.
- Various sexual perversions: trying to get Adam to mate with every animal under the sun, and keeping naked children locked in his walled garden where he walked around watching them.
4:1 And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the LORD.
The first phrase suggests that Adam and Eve did not have sex in the garden. That would be consistent with them being children, or just with them being innocent.
With her punishment in mind, I'd expect Eve to say, "I have gotten great pain from the Lord." This phrasing suggests that the God is as likely as Adam to have impregnated Eve.
Note that this use of the word "man" clearly means "male infant". So back when God first created Adam, calling him a man told us nothing about his age.
Cain is apparently the first person to be born. That's an accomplishment of sorts.
Have I mentioned that the author has a bit of an obsession with procreation?