Here is the full list of all 35 Planet of the Apes: Last Frontier achievements.
Where have all the good guys gone?
Maria accepts her fate
Apes together strong!
Jess puts her life on the line
A chilling ending
Bryn shows no mercy
Damn dirty apes
Best of all outcomes
Jess and Bryn sitting in a tree
Jess puts the big man in charge
An explosive ending
Mark demonstrates his feelings for Jess
A debt repaid
Bryn opens the way to peace
Complete Chapter 4
Thaw relationship with Mark
Bryn makes an important choice
Bryn demonstrates brotherly love
Jess does the right thing
Complete Chapter 3
A rather pointed decision
Jess does what's necessary
Bryn shows wisdom
Complete Chapter 2
Bryn is his father's son
Complete Chapter 1
Complete Prologue
Jess betrays confidences
Bryn is a family man
Juno's downfall
Bryn shows his true colours
Bryn prefers deeds to words
Jess looks a gift horse in the mouth
Bryn covers up a mistake
Set an ape on fire