What are some of the duties that Gigalmesh fulfills and fails to his people?(

When GIlgamesh is first introduced, we see a leader who is failing in his most important duties to his people. He fails to protect them, works them to the point of death, rapes newly married brides, and then leaves them.

The duties he fulfilled were in constructing temples to the gods. Gilgamesh's lineage is established as one-third mortal and two-thirds a god; thus, his temples were built and his people appealed to the gods when in need.

Upon his return, and after neglecting his people for a very long time, Gilgamesh does return and act like the king he was meant to be. That's in his favor!