A masterpiece. For free if you own Skyrim. What are you waiting for ?

I liked Skyrim (not enough to play it a second time on my Steam version though), I loved and worshiped Enderal. If I could have, I would have given my money to SureAI rather than to Bethesda. They deserve it more.
To me, everything about this mod surpasses the original game.

First, the story. While the lore of Bethesda's world, Tamriel, is rich, the story of Skyrim is pretty weak overall. That's about a civil war and dragons, with the mendatory Guilds and Daedric quests. That's pretty all, no surprise.
The lore of SureAI world, Vyn, is also very rich. The story of Enderal, though, is so far superior to Skyrim's. I won't spoil it, but I can say that it feels much more mature, credible, epic, intense and dangerous.
Expect themes like wars, religions (especially criticisms about it), purpose of mankind, diseases, destiny, chaos, threats beyond comprehension, with a severe portrait of humanity. Skyrim is fantasy, Enderal is dark-fantasy, which feels superior and more appealing to me.

The main story is brilliant and clever, from the first minutes to the very end(s). The secondary quests are either good or amazing. I cared about the quests, I cared about the characters, I cared about the choices to make. Don't rush the main quest or you will lose plenty. Enjoy every bit of it.

The soundtrack is fantastic. Obviously the soundtrack of Skyrim is also great, but lots of the musics are very similar, as Jeremy Soule seems to reuse sometimes his previous tracks. Was it a music from Skyrim, Neverwinter Nights, Icewind Dale, Guild Wars ? Hard to tell, they are sometimes almost the same.
Musics of Enderal are refreshing at least, and many of them are so good that I could (and did) loop them for hours.
And the bards songs, female or male, English or German, are wonderful (go listen Winter Sky/Das Lied vom Winterhimmel and The Aged Man).

The level-design feels different. In Skyrim and even more in Oblivion, you can go usually to every directions, the world is kinda flat, and you can quickly see most of the world, especially with early fast-travel. Some enjoy that sandbox-ish feel, I don't, as I tend to see too much too early.
Enderal feels more like Morrowind, with often the use of "paths" between mountains and hills. It's slightly more guided (though it's far from being linear), and I prefer that way, as there are still huge parts of the world to discover after dozens of hours.
The world is huge, probably smaller than Skyrim, but with more diversity, and also way prettier. I wanted to see everything.

The leveling has changed. Goodbye the level-up when you raise 10 times any skill, hello the good old RPG way, with experience points at kills, quests, lockpicking. At every level-up, you get X points to distribute among your skills. Gold has now a huge value, as you have to buy skill books to spend these points.

The labour of passion, love, patience and devotion of the team is omnipresent. The writing, the programming, the designing, the composition, the singing, the voice acting, the artistic creation, the translating, and so on : everyone did a perfect job, especially the main guy behind this project, Nicolas Lietzau. If only all game studios would be like that...

The few flaws, especially crashes once in a while and (rare) bugs, are actually all inherent to Skyrim's game engine. I then don't have even a single blame about this mod. Well, maybe a little one : quite a lot of missable achievements that require you to follow a guide to not have to replay two or three times a 130 hours long game if you want them all.

SureAI, you have my sincere and deepest respect, and I hope that you will give us more gems like Enderal and dreams in the future. Thank you so much. Stay true to yourselves.
I can't wait for Nehrim in 2020.