The core essence of a video game is the game feel (which not everyone likes, because it's ill-defined). How does a player interact with a game? Via game mechanics. No amount of polish is going to make up for horrible game mechanics.

Jan Willem (of Vlambeer), who hates the phrase "game feel", talks about it through a simple iterative process of improving game mechanics. See: https://www.youtube.com/watch?v=AJdEqssNZ-U