Main change:

You can refuse Almalexia's request to inflict Ashstorms on Mournhold. Doing so sets the main quest with her on an alternative path, where you will be her adversary much sooner. You'll revisit the same locations, but the encounters, voices and writing will be very different. 

Full changes:

1. Eno Romani will now give a voiced speech from the Winged Guar to whoever will listen. If you listen long enough to his speech, you can gain intel on his cult that you would otherwise have to dig around for.

2. The Dark Brotherhood has unique voiced attack lines.

3. The head of the Dark Brotherhood will have a voiced death scene, where he will admit to who has hired him, instead of a text box. The voice leaves less ambiguity to who the culprit is, making the player's later deduction from the letter more sensible.

4. You can infiltrate the Dark Brotherhood hideout disguised in their armor, with new voice lines if you do.

5. You can press Helseth with evidence that he ordered your assassination. While you may gain some insights into his fears, Kings do not like to explain themselves.

6. Almalexia will react to you differently if you've defeated Dagoth Ur on your first meeting. 

7. Fixed inconsistences between Almalexia regarding you as the Nerevarine. This is tied to your progress on the main quest, not to your quests to Almalexia. It is possible to complete the Tribunal quests without any reference to you being the Nerevarine. This will skip the sword of the Nerevarine quest entirely if you have not been named Nerevarine by Nabani Maesa.

8. Reordered Almalexia's quests. The ashstorms and fabricant attack are last, while the more sedate traitor Hand quest and investigating the cult come first. The goblin army and mazed band are at the start of the questline, as before.

9. Changed Rerlas Mon, seller of fine scribs and rats, to a Dunmer, so he can use the voice line that beth originally recorded for him.

10. Urvel Dulni now has unique attack voices and a voiced prayer as he cleanses the shrine.

11. Sotha Sil will give you the quest to reforge the blade of Nerevar if you skipped it with Almalexia. He will ignite the flame himself in this version of the quest.

12. Sotha Sil will lose his invulnerability once you have the Blade of Nerevar.

13. Azura and Sotha Sil will have a final encounter once you reforge Trueflame in the alternate ending.

14. In the optional download, Vivec will play music in memory of the dead at the end of the alternate quest.

15. 2.0 Update - Adds an incredible scripted bossfight to Almalexia in the alternative questline ending.