In The Epic of Gilgamesh, the images of Mesopotamian gods are represented in much the same way as Greek and Roman gods would be a thousand years later. First, many gods are attached to natural phenomena or occurrences. Shamash is the god of the sun (and his wife the goddess of the moon), Ishtar the goddess of both love and war, Ea the god of water and the arts, etc. Thus we see the attempt to explain natural occurrences through religion. This is popular in ancient mythologies and polytheistic religions. Monotheistic religions have the same aspects, but since they focus around one god, all natural phenomena are wrapped up in his control.
Second, the gods are heavily personified. They have relationships, they pick favorite mortals to guide (or hold grudges against others and attempt to destroy them), they fight amongst themselves. When Enlil chooses to destroy mankind in the Flood, Ea saves Utnapishtim by telling him to build the boat. When the Flood is at its fiercest, Enlil is safe within his palace, while the other gods are cowered around the gates, soaking and miserable. This is reflected in the gender divisions as well. The king of gods is male, which suggests a masculine dominance. Yet Ishtar is a major goddess, controlling both love and war, and the city of Uruk is dedicated to her. Because she controls two aspects of human nature ruled by emotion, it may suggest that women are guided by instinct or emotion more than reason.
The images of the afterlife are strange. The underworld is certainly dark, and it appears that all souls alike are trapped underground, to shuffle about like birds. Because this is such a fragmentary look at the beliefs, it is difficult to form an accurate picture of their vision of the underworld.