The details are where the players fall in love with your game
This card wasn't meant to cause any major impact, but it did. The card itself wasn't powerful. The impact came from a little creature on the top of the dragon's head. It's called "Fblthp" (can't pronounce it). Players fell in love with it and produced a lot of montages, memes to the point that the company itself sold products based on it. This proves that very often the players are very passionate about little details in a product. Players can be very passionate about an artist or a character as in this case.
The lesson here is that grandiose things or things that are common attract too much attention. Players have a natural desire to seek individuality within the game and to do so they are naturally attracted by small details, as in the case of the creature above. This is true for the game as a whole. Some players are attracted by lightning bolts. Some players are attracted by angels. Some players are attracted by a character. Some players love a certain type of card. There are unlimited details, some larger than others, that attract players in some direction. Often the impact of such small details is underrated or wasn't predicted.
Does this apply to level design? Yes. Very often the players fall in love with some small detail in a game. It can be a particular level among all levels. It can be a character among all other characters. It can be the clothes that a character wears. It can be a certain room from a level, a small piece of a level. It can be a poster in a level. Some players feel delighted with the level's background, mountains for example. There are also players who experience joy with a scene such as a body placed on a chair inside a building for example (I'm talking about beauty, not about dark thoughts mind you). Many other details can capture a player's attention such as sounds, textures, lights and it could even be non intentional or predicted by whoever made the level.
Bioshock is a good example in regards to players loving small details. The level design in this game takes great care to small details. There are so many details that there is a whole class of players that are absolutely crazy about this game. The atmosphere as a whole is unique. Going deeper (pun intended) and players find many things to bound with. Small things such as a key on a table can have great value to create the unique experience on this game. The underwater world of Rapture has many fans around the world and each of these fans have one or another particular aspect that they are most attached to. What Mark has said about small details having great importance to players is true for many of the fans of Rapture.
