The game is packed and uploaded again (...again!) and the achievements seemed to be back now!
It was probably because the old version had some problem with Steam update or something...anyway I think it's finally okay!
*It still won't pop out when you playing, but it'll be unlocked in your achievement list.
Thank you for reporting, and I cannot thank you enough for your patience and understanding.
Phew.
Take care & have a nice dayːtwtpbearː