The term “roguelike” initially referred to any title similar to “rogue”. As the subgenre grew in popularity, players and developers felt they needed a more concrete definition that outlined the facets of gameplay a title needed to qualify. The first meeting of the International Roguelike Development Conference took place in 2008 in Berlin, Germany. Here the first definition of the subgenre was created.
According to RogueBasin.com, there are nine “high value factors” and six “low value factors” that determine whether a game is a roguelike. High-value factors include: random environment generation, permadeath, turn-based combat, grid-based navigation, one mode, complex problem-solving, resource management, hack ‘n’ slash combat, and exploration and discovery. Then there are the low value factors: a single player character, character-like monsters, tactical challenge, ASCII display, dungeons, and displaying numbers like hit points and attributes. They called this the Berlin Interpretation.
It is not necessary for a game to meet all of the criteria listed in the Berlin Interpretation to be classified as part of the roguelike subgenre, but the more it has, the more “roguelike” it is considered.