Well, this was unexpected in many ways. Let us then dwelve into this civ!
UA - Epic Quest: When you capture a barbarian outpost, you get a tribal village reward.
Simple yet effective and more importantly,
active unique. It also fits Sumeria's "early civ" role. I would have liked some kind of agricultural bonus better, considering that Sumeria was the one civ that kickstarted this whole "sedentarism" thing, but so far, so good.
UU - War Cart: No penalties to fighting Spearmen or other anti-cavalry units. Extra movement if starting on flat terrain. 30 strength.
Wow, if this unit is avaible from the very start of the game this could really help you to make early zerg rushings and all kind of cheesing tactics. Scary, yet exciting!
UI - Ziggurat: Grants culture and if adjacent to a river, science. Cannot be built on a hill.
At last, long last, an early technologic civ! This improvement seems to be incredibly powerful.
LUA - Adventures with Enkidu: During a Joint War, Sumeria shares pillage rewards and combat experience with closest allied unit within 5 tiles. Doesn't get warmonger penalties when fighting for your allies.
Errrrr sorry, but I don't like this one. Not one bit. I really get that they are going with the "Gigamesh is a bro, broh" theme, but seriously: NOPE. Sumeria was never about joint wars nor being a good ally. Agriculture, relics, culture, city planning... there are many angles to the Sumerian civilization, yet they choose this view... it is a pity, seriously. This is anti-inmersive, and it seems only useful in multiplayer games. While I love Gigamesh model and personality, this LUA breaks the civ's flavour, rather than enhance it :/