You will obtain this by getting an A ranking in all possible stages in one play through. Know that Stage 3 is an automatic S ranking. The proper choices are as follows:
Stage 1:
- Choose curry.
- Nothing beats curry.
- Eat the food yourself.
- Okay.
Stage 2:
- Recheck the questions.
- Elementary school test.
- 2.
Stage 3:
- Let Akio go first.
- Stop Him.
Stage 4:
- Look at the treasures in the back.
- Take the old ring that is somehow familiar to you.
- Take his hand normally.
Stage 5:
- Stop Akio.
- A tasty bone.
- Imagine a puppy.
- Keep petting.
Stage 6:
- Imagine the little Akio.
- It isn't like that.
Note: You will need to play through the end sequence and credits for the achievement to pop.