As gods

3:5 For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil.

The serpent is not only asserting that God is lying about the fruit being poisonous, but that God is doing so for petty motives.  Either God is trying to maintain power, or God is afraid of people,  or perhaps God just enjoys watching people living in ignorance.

Further, the serpent is ascribing impressive magic powers to the fruit; the tree, according to the serpent, lives up to its name.

This strongly suggests that God is not alone, not single, but one of gods, a group who know good and evil.

If this is all a metaphor or a story of childhood, then "gods" are adults, and God is an adult who doesn't want these children to grow up.  So God lies to keep the children from the fruit, which presumably represents experience.

The phrase "your eyes shall be opened" is clearly metaphorical.  This again means that it really isn't possible to take the Bible entirely literally.

One interesting note is that the phrase "in the day ye eat thereof" here parallels
"for in the day that thou eatest thereof" from God's admonition in 2:17.  Again, this suggests that the serpent was somehow aware of that.

Ok, we all know that lying is wrong, that honesty is the best policy.  And either God is lying or the serpent is (or perhaps both), so clearly one of them is bad.