Here is the full list of all 15 Sakura Alien 2 achievements.
Get hugged by Ena
Say goodbye to Hiyori
See Hiyori in her alien clothes
Let Ena and Hiyori say their goodbyes
Let Aloe Explain everything
Hiyori storms into the office
Give Ena a pat on her head
Visit Ena at her job
Get fed by Hiyori
Doesn't this only happen in fanfic?
"Catch" Professor Sakai
Watch Hiyori brush Ena's hair
Meet this woman for a second time
Watch someone trip and fall
Let Ena be your alarm