Wroth

4:5 But unto Cain and to his offering he had not respect. And Cain was very wroth, and his countenance fell. 

I'd be wroth, too; wouldn't you?  I think that wroth means "pissed off".  And "his countenance fell" means "he looked sad."

Ok, Cain grew fruit and Abel grew sheep.  And Cain offered up to God some fruit and Abel some sheep.  Why they made offerings to someone who so badly mistreated their parents is one question.  Regardless, they clearly offered what they had to offer.

God, that day, was apparently not in the mood for fruit.  And he was rude about it.  No explanation is given; the only option we have is simply assuming that God was being a jerk or a troublemaker.  And he mistreated Cain, which seriously bummed Cain out.

Firstlings

4:4 And Abel, he also brought of the firstlings of his flock and of the fat thereof. And the LORD had respect unto Abel and to his offering:

Because who wouldn't want some young sheep fat?

Offering

4:3 And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto the LORD.

I don't understand the whole concept of offerings to God.  Apparently I'm not alone; the practice seems to have died out.  Cain's giving God food because God's hungry?  Because God is wildly insecure and needs gifts to feel good about himself?

And Cain is grateful to God because God made farming difficult?  Because God made snakes bite Cain's heels?

The open phrase is a very windy version of "eventually".  But it wasn't necessary to point out the passage of time between Cain and Abel being born and them getting occupations.

Tiller

4:2 And she again bare his brother Abel. And Abel was a keeper of sheep, but Cain was a tiller of the ground. 

What, no computer programmers?  Did Cain start tilling when he was an infant?

Anyway, still agricultural.

Gotten

Ok, before we move onto chapter 4, let's summarize all the evil things God did during the course of the garden of Eden story.

1. 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.
2. 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.
3. Lying to them.  God claimed the fruit of the tree of knowledge was poisonous, when he knew it was not.
4. 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.
5. 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.
6. 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.
7. 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.
   

All in all, this Lord God seems to be morally bankrupt at best.  The garden story goes from 2:4 to 3:24, for a total of 46 verses.  And in that short span, God racked up a pretty impressive list of sins.  Yet somehow, people interpret this as God is good.  In contrast, the serpent's entire little part in the story was telling the truth and getting punished; and people interpret this as the serpent is evil.  Two conclusions completely unsupported by the text.

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?

Flaming sword

3:24 So he drove out the man; and he placed at the east of the garden of Eden Cherubims, and a flaming sword which turned every way, to keep the way of the tree of life.

I like the fact that we are given directions to Eden earlier, and it should just be somewhere with some Cherubs guarding it and a cool spinny flaming sword.  And there's only one way in.

A Cherub is a kind of angel.  The word "Cherubim" is the plural.  I'm not sure what "Cherubims" is supposed to be, exactly.

All this trouble explicitly because God is afraid that man might live forever.  How does that threaten him?

Forth

3:23 Therefore the LORD God sent him forth from the garden of Eden, to till the ground from whence he was taken. 

Again, the woman is not mentioned here.

This is strongly agricultural.  The punishment is being sent from a garden to a farm.  One way to interpret this is as being about the start of agriculture.  It started in a place where you didn't have to know much about agriculture to farm; it was easy.  That's fairly obvious, because nobody had any technical agricultural knowledge before they engaged in agriculture.  But as they gradually ruined the soil with bad technique, they also learned better technique.  Still, agriculture became more and more difficult.  Where once they could grow things easily, as in a garden, later it was hard, as on a farm.

Iraq is a desert today.  That is the result of one of mankind's worst environmental disasters.  Before we started farming there, it was one of the most fertile places on earth.