Direct quote
“I really don't like saying this, but it really wasn't up to my standards. The care that I put in the original wasn't there.”
What it documents
Kojima said his Metal Gear for the MSX was very well received and was later converted to Famicom without his involvement. He added that he does not like to say it, but the Famicom version was not up to his standards: it lacked the care of the original, was more difficult, at the fortress entrance dogs could kill the player outright, the fun stealth element was missing, and the actual Metal Gear, the robot, does not appear in the game.
Source
Gamers Today, interview with Hideo Kojima (undated page, retrieved from web.archive.org). View source ↗
“The fun stealth element was not there, and the actual Metal Gear, the robot, doesn't appear in the game.”