For Memories of East Coast players, iIn order to obtain all the achievements, only one playthrough is needed, but you will have to save and reload at specific points (or use mouse wheel up to go back to the choice and pick a different option). These are mentioned in this guide.
Walkthrough
➡️ No

It’s good to see you here.
➡️ Go back to sleep
➡️ Can’t sleep

Can’t sleep!
➡️ [Any]
➡️ [Any]
East Coat Night Time
💾 SAVE POINT 1 (at the choice: Ask mom / Ask Dad)
➡️ Ask mom about stars

Raised good.
🔄 RELOAD SAVE POINT 1
➡️ Ask Dad

Like father like son.
East Coast
➡️ [Any] (but maybe “Give a moment” is better)
Leisure Park, East Coast
➡️ [Any]
💾SAVE POINT 2 (at the choice: Curious / Concerned)
➡️ Curious

And He found you lost and guided [you],
🔄RELOAD SAVE POINT 2
➡️ Concerned

And speak to people good [words]
Turlene Highway
➡️ Take a look
💾SAVE POINT 3 (at the choice: Play with toy / Change radio)
➡️ Play with toy

I love unicorn!
🔄 RELOAD SAVE POINT 3
➡️ Change radio

Let’s hope there’s birthday song playing on the radio!
💾SAVE POINT 4 (at the choice: Uncertain / Friendly)
➡️ Uncertain

And do not mix the truth with falsehood or conceal the truth while you know [it].
🔄RELOAD SAVE POINT 4
➡️ Friendly

And there is none comparable to Him.
Icecream cart
➡️ [Any]
➡️ [Any]
💾SAVE POINT 5 (at the choice: Walk away / Pay)
➡️ Walk away

Guide us to the straight path –
🔄RELOAD SAVE POINT 5
➡️ Pay

let not the worldly life delude you
Eating icecream
➡️ [Any] (first option is nicer)
Home
➡️ [Any]
➡️ [Any]
➡️Ignore

Abdullah ibn Amr reported: The Prophet, peace and blessings be upon him, said,
“Verily, the spirits of two believers will meet throughout the day, even if they do not see each other.”
Source: al-Adab al-Mufrad 261 Grade: Hasan (fair) according to Al-Bukhari
➡️ [Any]
Salina’s hospital
➡️ [Any]
💾SAVE POINT 6 (at the choice: Tell her / Keep it a secret)
➡️ Tell her

And ease for me my task
🔄RELOAD SAVE POINT 6
➡️ Keep it a secret

And We removed from you your burden
Present Day
💾SAVE POINT 7 (at the choice: Accept Fate / Ignore Fate)
➡️ Accept Fate

He will give you [something] better than what was taken from you,
🔄RELOAD SAVE POINT 7
➡️ Ignore Fate

and be patient over what befalls you. Indeed, [all] that is of the matters [requiring] resolve.
Watch the credits until the end (songs list)
Click on the two people (or in the area around them for a bit)

Wonderful, you found the secret achievement!