The moment you say “We are going to make a game that is a <genre> with <art-style> graphics” and commit to developing that game you have made about 90% of your marketing decisions for your game.

SteamDataSuite.com published a collection of Indie game data from Steam. It continues to echo the conclusions of Chris Zukowski from How to Market Your Game helps lots of game developers market their games.

The games with green titles where the majority surpass the $5000 revenue bar, the uncolored entries are medium sellers, and red are low.

If you make a great 4X game, it shouldn’t be hard to stand out among the +-/25 games 4X games released in the same year. But even if you make a great Puzzle game, it will be challenging to generate traction if there are +/-1000 other games in the segment waiting to be discovered. So coming back to what the article on howtomarketyourgame.com suggested: Yes, a lot of your game’s market potential is determined by the genre or rather segment you chose, but not necessarily because there is a lack in popularity, but rather because it will be hard to win through the hundreds or thousands of other games released in the same segment

Which echos what How to Market Your Game concluded.