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