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.
Beat the Omega Weapon
Defeat every member of the CC group
Reach SeeD rank A
Collect all Timber Maniacs magazines
Kill 1000 enemies
Finish the game
Unlock Guardian Force Eden
Complete the PuPu side quest
Complete the Obel Lake side quest
Capture a Chocobo
Unlock Guardian Force Bahamut
Unlock Guardian Force Cactuar
Reach maximum HP
Unlock Guardian Force Doomtrain
Unlock Guardian Force Tonberry
Draw magic 100 times from draw points
Find Ragnarok
Lose a rare card in a Triple Triad game
Unlock Guardian Force Alexander
Unlock Guardian Force Cerberus
Unlock Guardian Force Pandemona
Upgrade your weapon
Unlock Guardian Force Leviathan
Unlock Guardian Force Carbuncle
Unlock Guardian Force Brothers
Play Triple Triad
Draw (Stock) magic from enemies 100 times
Unlock Guardian Force Diablos
Kill 100 enemies
Get your first salary from SeeD
Unlock Guardian Force Siren
Unlock Guardian Force Ifrit
Unlock Guardian Force Shiva
Unlock Guardian Force Quezacotl