0.0% of players have that achievement. That includes developers.

As much as I've played the game, I dont have many of the achievements. . . I havent looked at why but I am sure some of them can only be done via multiplayer, which isnt gonna be me... and I dont tend to use the combos as much as I should since its not usually needed (bone+sharpened+2ndCoating+trinket with a little timing will wipe the entire map pretty easy).

I'm in the same boat as you, OP. I've built every variant of every item on the decoration tab and still no achievement. I also can't figure out how to accomplish the petting for 20 seconds one...

I have 9 hidden achievements, no idea what they are - can someone point me to the master list?

Agrivar の投稿を引用：

I also can't figure out how to accomplish the petting for 20 seconds one...

Hold the petting key down and dont let up until you have the achievement

The one that bothers me is "Somewhat of an explorer", where you have to explore 2 new biomes. Since I have reached the 3rd biome with 2 separate characters, I kinda feel I should have that one.... there must be a trick to it....

No trick when I got it; as soon as I set foot on a Red Cliffs island, the achievement popped up. This was not a fresh world, so the patch updates don't seem like a suspect to me.

I don't know why it wouldn't trigger for you.