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