Here is the full list of all 26 STEINS;GATE ELITE achievements.
Played through everything in STEINS;GATE ELITE
Asked by Kurisu to buy cup noodles twice in a row.
Reached Kurisu's ending.
Completed all endings.
Reached Luka's ending.
Reached Steins Gate.
Saw all TIPS.
Chapter 10 Clear
Offered tea by Faris.
Made friends with Kurisu via email.
Learned about Luka's relationship to his sister.
Reached Suzuha's ending.
Reached Mayuri's ending.
Chapter 9 Clear
Chapter 8 Clear
Chapter 7 Clear
Reached Faris's ending.
Chapter 6 Clear
Chapter 5 Clear
Learned why Mayuri started making costumes.
Chapter 4 Clear
Received an unusual proposition from Suzuha.
Chapter 3 Clear
Chapter 2 Clear
Chapter 1 Clear
Prologue Clear