Here is the full list of all 49 BLUE REFLECTION: Second Light achievements.
Develop a facility for the first time.
Go on a date for the first time.
Recover Kokoro's memories.
Repair the leak at the school.
Cut grass 50 times.
Fulfill a request for the first time.
Craft an item for the first time.
Obtain all Achievements.
Recover Shiho's memories.
Recover Hinako's memories.
Recover Rena's memories.
Recover Kirara's memories.
Recover the Hirahara Sisters' memories.
Recover Yuki's memories.
Recover Yuzu and Lime's memories.
Recover Uta's memories.
Create Origin Gate.
Raise Ao's Talent level to maximum.
Raise Kokoro's Talent level to maximum.
Raise Rena's Talent level to maximum.
Raise Yuki's Talent level to maximum.
Raise Shiho's Talent level to maximum.
Raise Hinako's Talent level to maximum.
Raise Kirara's Talent level to maximum.
Raise Hiori's Talent level to maximum.
Raise Mio's Talent level to maximum.
Raise Uta's Talent level to maximum.
Craft 25 different items.
Craft 50 different items.
Develop 15 facilities.
Develop 30 facilities.
Fulfill 25 requests.
Fulfill 50 requests.
Go on 25 dates.
Go on 50 dates.
Go on 100 dates.
Activate Ether Tide for the first time.
Activate Ether Tide with all characters.
Activate a One-on-One Finisher for the first time.
Use an item to remove an obstacle from a path for the first time.
Develop the bath.
Explore all locations.
Collect all memory shards.
Get Ao to level 50.
Get all characters to level 50.
Access 10 different school facilities.
Defeat "The One Who Fell from the Sky."
Defeat "The One Who Came from Nothing."
Defeat "The World."