I have to revise my stance on this game: Endless Space is brilliant. And now I will tell you why, and you will like the answer:
Endless Space is not linear.
Okay, I might have read too much on game theory, but I will translate this in Civ-terms, because that's a language we all speak. Civ is very linear. You start your first city, you start building something from a list that is presented to you, you start researching something from a list that is presented to you. Basically, the game plays itself: because there is a limited number of options presented to you, it's very hard to make the wrong choice. At this point, we enter a debate on why there are so many wrong choices in civ, and how brilliant we are because we make the right choices and a lot of people struggle on warlord. Especially for you I will rephrase that critical sentence: because there is a limited number of options presented to you, it's very hard to make the wrong choice. What, I did it again? Okay, it might just be me, but I find it very difficult to do something wrong in Civ. Whatever you do, it's not wrong anyway, you'll just fall behind. In Civ, falling behind is lethal.
Now we get to the part where I tell you why Endless Space is such a great game. Endless Space doesn't have a linear tech tree. Civ's tech tree is very linear: to get further up the tree, you just have to research techs that come before it, and basically you just have to research (or tech whore) everything (give or take a few techs). Endless Space's tech tree is split into different branches. Take a look at this picture of Endless Space's tech tree:
That's beaucoup techs, right?
The best thing is that you can simply ignore whole branches. The tree is pretty lenient on prerequisite techs as well (you might research something without researching the techs leading to it, in some cases), so you might even ignore a large part of the branch you are researching. Because the tech tree allows for more freedom, it's easier to be different than your opponents as well. But it's also easier to screw up, and that's what makes the game difficult. Civ is "do everything right, get ahead, win", whereas Endless Space is "hmm let's see, what do I want to do now?". And because research is FAST, you get more options in a short time. This gives you the feeling you have a lot of freedom to do what you want: it's just a feeling though, especially in the beginning you're still limited. But with every new tech you get more choices: different buildings, colonization options, ship modifications, empire modifiers. And unlike Civ, you don't need to pick all options, you could just ignore them.