Here is the full list of all 12 sweet pool achievements.
Complete all achievements.
Unlock all CGs.
Unlock all music.
Unlock the bonus illustration.
Unlock the full version of the opening song.
Reach Tetsuo's second ending.
Reach Tetsuo's third ending.
Reach Makoto's ending.
Reach Zenya's ending.
Reach Tetsuo's first ending.
Reach the Miracles may ending.
Unlock the Miracles may route.