With the appropriately titled “Asimov” update, Paradox has added a variety of free features to their sci-fi epic, Stellaris.
Asimov focuses on improving Stellaris‘ mid-game, which was heavily criticized in the original reviews. Diplomatic events will spice up (or spice down) relationships between you and fellow space faring civilizations. In another major gameplay tweak, foreign border access will always be available unless you anger your neighbor into denying access. Many new diplomatic features will also be available.
Furthermore, aside from gameplay changes, Asimov adds a list of new visual enhancements: solar system skyboxes have been drastically improved, and battle stats have been altered to make space combat more exciting and fluid.
Additional balance changes have also been made to previously underpowered ethics. Militarist and Pacifist ethos have received significant buffs, and should be more appealing when making a competitive choice.
If you want to read the full list of patch notes, you can find it here.