People use the word "graphics" and "sound" often, but that's not all that makes a game. So many indie "ugly" games work out just fine. It's all about the gameplay. You can make the graphics and the sound be a core part of that, but you can also focus on other places.

Factorio and Dwarf Fortress are two examples of those. Can someone say their graphics are amazing? Probably not. Yet they focused on their differentials: the unique gameplay.

I have to agree with the GP. They're always unique in one form or another.

People however overuse the marketing card IMO, saying that you need a lot of marketing. Good games do stand out for being good games. Word of mouth only works if your game is good. Nobody will urge their friends to play a bad game and for indie games, word of mouth is king. You can't "force" word of mouth marketing, so it's not really a marketing effort. It comes naturally with good games.