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