There are a large number of achievements in Beast of Reincarnation, and many of them are quite complex to complete. For example, the "Closest Companion" achievement requires reaching maximum intimacy with Xiao Ku. It's not particularly difficult; just pet him regularly and take your Dog.exe for baths, and you'll reach max intimacy by Chapter 4.
How to Unlock All Achievements in Beast of Reincarnation
Description | Platinum Trophy Primer