Here is the full list of all 12 Palworld achievements. It takes around 80-100 hours to unlock all of the achievements on Windows.
Defeated Victor & Shadowbeak
Defeated Marcus & Faleris
Caught 10 kinds of Pals
Caught 20 kinds of Pals
Caught 50 kinds of Pals
Caught 90 kinds of Pals
Defeated Axel & Orserk
Defeated Lily & Lyleen
Defeated Zoe & Grizzbolt
Caught first Pal