Here is the full list of all 34 FINAL FANTASY VIII - REMASTERED achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Finish the game
Beat the Omega Weapon
Unlock Guardian Force Siren
Kill 1000 enemies
Unlock Guardian Force Eden
Defeat every member of the CC group
Collect all Timber Maniacs magazines
Complete the PuPu side quest
Unlock Guardian Force Doomtrain
Unlock Guardian Force Cactuar
Reach maximum HP
Unlock Guardian Force Bahamut
Complete the Obel Lake side quest
Find Ragnarok
Draw magic 100 times from draw points
Unlock Guardian Force Tonberry
Capture a Chocobo
Unlock Guardian Force Alexander
Unlock Guardian Force Cerberus
Unlock Guardian Force Pandemona
Unlock Guardian Force Leviathan
Unlock Guardian Force Diablos
Reach SeeD rank A
Unlock Guardian Force Carbuncle
Unlock Guardian Force Brothers
Upgrade your weapon
Lose a rare card in a Triple Triad game
Kill 100 enemies
Draw (Stock) magic from enemies 100 times
Get your first salary from SeeD
Play Triple Triad
Unlock Guardian Force Ifrit
Unlock Guardian Force Shiva
Unlock Guardian Force Quezacotl