>>14259908
High value factors
Random environment generation
The game world is randomly generated in a way that increases replayability. Appearance and placement of items is random. Appearance of monsters is fixed, their placement is random. Fixed content (plots or puzzles or vaults) removes randomness.
Permadeath
You are not expected to win the game with your first character. You start over from the first level when you die. (It is possible to save games but the savefile is deleted upon loading.) The random environment makes this enjoyable rather than punishing.
Turn-based
Each command corresponds to a single action/movement. The game is not sensitive to time, you can take your time to choose your action.
Grid-based
The world is represented by a uniform grid of tiles. Monsters (and the player) take up one tile, regardless of size.
Non-modal
Movement, battle and other actions take place in the same mode. Every action should be available at any point of the game. Violations to this are ADOM's overworld or Angband's and Crawl's shops.
Complexity
The game has enough complexity to allow several solutions to common goals. This is obtained by providing enough item/monster and item/item interactions and is strongly connected to having just one mode.
Resource management
You have to manage your limited resources (e.g. food, healing potions) and find uses for the resources you receive.
Hack'n'slash
Even though there can be much more to the game, killing lots of monsters is a very important part of a roguelike. The game is player-vs-world: there are no monster/monster relations (like enmities, or diplomacy).
Exploration and discovery
The game requires careful exploration of the dungeon levels and discovery of the usage of unidentified items. This has to be done anew every time the player starts a new game.
Low value factors
Single player character
The player controls a single character. The game is player-centric, the world is viewed through that one character and that character's death is the end of the game.
Monsters are similar to players
Rules that apply to the player apply to monsters as well. They have inventories, equipment, use items, cast spells etc.
Tactical challenge
You have to learn about the tactics before you can make any significant progress. This process repeats itself, i.e. early game knowledge is not enough to beat the late game. (Due to random environments and permanent death, roguelikes are challenging to new players.) The game's focus is on providing tactical challenges (as opposed to strategically working on the big picture, or solving puzzles).
ASCII display
The traditional display for roguelikes is to represent the tiled world by ASCII characters.
Dungeons
Roguelikes contain dungeons, such as levels composed of rooms and corridors.
Numbers
The numbers used to describe the character (hit points, attributes etc.) are deliberately shown.