Yes, fine tune the fundamentals of "is this thing fun to control". Content is a separate thing which I personally think is where a lot of modern games have gone wrong.

Nintendo are known for developing prototypes to figure out what is fun. Unlike modern "implement the design doc" process. There's a YouTube interview with someone from retro studios who explains this, Nintendo weren't interested in their design docs for metroid. I am hopeful remembering this correctly.

I haven't read this Goddard interview yet, but he was responsible for one of the best games of all time, 1080 snowboarding! What is completely bananas is that him and his mate ended up working at Nintendo and showing them how to do 3d graphics when they were teenagers.