To give more information, you still need to do the exact same things as before to achieve
perfection:
- get all 4 obelisks
- get all stardrops
- get all monster slayer achievements
- find all golden walnuts
- get full shipment achievement
- cook every recipe
- craft every item
- ...
However, a new fish, new items, new recipes and new products were added in the last update. This means that there is extra work to do to fullfill these four achievements in 1.6 compared to their 1.5 version.
The good news is that if you've already reach perfection on a save, you still have the achievement and the related rewards when loading this save file in update 1.6.