Here is the full list of all 35 Planet of the Apes: Last Frontier achievements.
Jess betrays confidences
Where have all the good guys gone?
Damn dirty apes
Jess does what's necessary
Apes together strong!
Jess puts her life on the line
Maria accepts her fate
Bryn shows no mercy
A chilling ending
Jess looks a gift horse in the mouth
Juno's downfall
A rather pointed decision
Bryn prefers deeds to words
Bryn shows his true colours
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 is a family man
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
Set an ape on fire
Bryn shows wisdom
Complete Chapter 2
Bryn is his father's son
Bryn covers up a mistake
Complete Chapter 1
Complete Prologue