Direct quote 1996
“That was when I came up with the idea for Policenauts, and I once again realized, as I had for a long time already, that things I want to do with games are best expressed in the adventure genre.”
What it documents
In 1996 Kojima said the design plans for Policenauts were very old: he first came up with the idea during development of the PC-88 and MSX versions of Snatcher, when they ran into problems caused by memory limitations and had to stop in the middle of development; he added that at that time he once again realized, as he had for a long time, that the things he wants to do with games are best expressed in the adventure genre.
Source
shmuplations.com; unofficial English translation of a 1996 Japanese interview preserved by the GSLA. View source ↗
“The design plans for Policenauts are actually very old. During the development of the PC-88 and MSX versions of Snatcher, we encountered various problems all related to the limitations of the memory, and had to take a break in the middle of the development.”