Here is the full list of all 75 Planet Stronghold 2 achievements.
Unlock Cliff romance CG (playing as Joshua)
Unlock Lakadema romance CG (playing as Joshua)
Unlock Milo romance CG (playing as Joshua)
Unlock Rebecca romance CG (playing as Joshua)
Unlock Rumi romance CG (playing as Joshua)
Unlock Shiler romance CG (playing as Joshua)
Unlock Avae romance CG (playing as Lisa)
Unlock Damien romance CG (playing as Lisa)
Unlock Lakadema romance CG (playing as Lisa)
Unlock Michelle romance CG (playing as Lisa)
Unlock Milo romance CG (playing as Lisa)
Unlock Tom romance CG (playing as Lisa)
Recruit the starting members while being drunk
Reach 20 successful skill checks in a single playthrough
Fail 20 skill checks in a single playthrough
Complete the quest 'it begins' before the deadline
Complete the sidequest in Outpost Three
Complete the sidequest in Outpost Seven
Complete the sidequest in Outpost Eleven
Complete the quest 'it begins' without using violence
Complete the side-quest 'War Crimes'
Survive the assassination attempt
Complete the side quest 'Bat Infestation'
Defeat the giant antlion in Sector Ypsilon-5
Complete the side-quest 'Water Thieves'
Complete the side-quest 'Free The Oasis'
Complete the side-quest 'Solar Power'
Peacefully solve the problems in Outpost 5
Complete the side-quest 'Outpost Siege'
Admire yourself in the gym scene
Survive the first encounter with Palidrayans
Complete successfully the Terrorist Threat quest"
Complete successfully the 'Knowledge Is Power' quest
Complete successfully the 'Jungle In Flames' quest
Fail both chapter 2 first main plot quests
Complete only one of the first two main plot quests on chapter 2
Complete both the chapter 2 first main plot quests
Complete the sidequest 'Seek And Destroy'
Complete the first raid of the game in chapter 2
Survive the siege of Zero-One
Become a neutral colony
Have over 25 unread email messages
Have over 50 unread email messages
Survive the surprise Pharguls encounter in Sector Delta-4
Complete the quest 'First Aid'
Defeat the Apex Alpha in Sector Delta-4
Tell a potential love interest that you're only friends
Complete the quest 'Medicines Production'
Complete the quest 'The Interview'
Complete the quest 'Trading Agreement'
Complete the quest 'Eye For An Eye'
Complete the quest 'Three Oases'
Side with Cullen in Sector Zeta-11
Complete the quest 'Stop The Descoria'
Complete the quest 'Memories Of Lucius'
Impress Gustavo when you first met him
Save Empire strike force during Volcano Raid
Side with Lakadema in Chapter 4
Side with Cullen in Chapter 4
Side with Shiler in Chapter 4
Side with Gustavo in Chapter 4
Complete the quest 'Spare Parts'
Complete the quest 'Gustavo'
Defeat 3 waves of enemies with Philipp in Chapter 4
Unlock the ending 'A New Home'
Unlock the ending 'From The Inside'
Unlock the ending 'The Big Escape'
Unlock the ending 'Mercenaries'
Unlock the ending 'Back For You'
Unlock the ending 'Space Pirates'
Unlock the ending 'Ruthless Commander'
Unlock the ending 'Selfless Hero'
Unlock the ending 'The Sacrifice'
Unlock the ending 'The Peace'
Unlock the ending 'Unstoppable'