Coming from an IGN article...
As I entered a shop to buy some upgrades and save my game, Amaya pointed out a purple cat at the counter with a cigarette in his mouth. I immediately asked why it was there and Amaya replied that he didn't know. Amaya said he has fond memories of the first time he played Metroid and how the world felt interesting and compelled him to continue exploring. It's something he tries to capture in all of the games he creates. As a result, he doesn't dwell too much on certain visual ideas as long as it just feels right in line with the game.
That Metroid influence is definitely clear in Pixel's games, which is why I love them so much. Can't wait to get my hands on Gero Blaster.