The game world is virtually infinite and procedurally generated as players explore it, using a map seed that is obtained from the system clock at the time of world creation (or manually specified by the player). There are limits on vertical movement, but Minecraft allows an infinitely large game world to be generated on the horizontal plane. Due to technical problems when extremely distant locations are reached, however, there is a barrier preventing players from traversing to locations beyond 30,000,000 blocks from the center.nb The game achieves this by splitting the world data into smaller sections called "chunks" that are only created or loaded when players are nearby. The world is divided into biomes ranging from deserts to jungles to snowfields; the terrain includes plains, mountains, forests, caves, and various lava/water bodies. The in-game time system follows a day and night cycle, and one full cycle lasts 20 real-time minutes.
New players have a randomly selected default character skin of either Steve or Alex, but the option to create custom skins was made available in 2010. Players encounter various non-player characters known as mobs, such as animals, villagers, and hostile creatures. Passive mobs, such as cows, pigs, and chickens, can be hunted for food and crafting materials. They spawn in the daytime, while hostile mobs—including large spiders, skeletons, and zombies—spawn during nighttime or in dark places such as caves. Some hostile mobs, such as zombies, skeletons and drowned (underwater versions of zombies), burn under the sun if they have no headgear. Other creatures unique to Minecraft include the creeper (an exploding creature that sneaks up on the player) and the enderman (a creature with the ability to teleport, pick up, and place blocks). There are also variants of mobs that spawn in different conditions; for example, zombies have husk variants that spawn in deserts.
Many commentators have described the game's physics system as unrealistic. Liquids continuously flow for a limited horizontal distance from source blocks, which can be removed by placing a solid block in its place or by scooping it into a bucket. Complex systems can be built using primitive mechanical devices, electrical circuits, and logic gates built with an in-game material known as redstone.
Minecraft has two alternative dimensions besides the overworld (the main world): the Nether and the End. The Nether is a hell-like dimension accessed via player-built portals; it contains many unique resources and can be used to travel great distances in the overworld. The player can build an optional boss mob called the Wither out of materials found in the Nether. The End is a barren land consisting of many islands. A boss dragon called the Ender Dragon dwells on the main island. Killing the dragon cues the game's ending credits and a poem written by Irish novelist Julian Gough. Players are then allowed to teleport back to their original spawn point in the overworld and continue the game indefinitely.
The game consists of five game modes: survival, creative, adventure, hardcore, and spectator. It also has a changeable difficulty system of four levels. For example, the peaceful difficulty prevents hostile creatures from spawning, and the hard difficulty allows players to starve to death if their hunger bar is depleted.
Survival mode
In survival mode, players have to gather natural resources such as wood and stone found in the environment in order to craft certain blocks and items. Depending on the difficulty, monsters spawn in darker areas outside a certain radius of the character, requiring players to build a shelter at night. The mode also has a health bar which is depleted by attacks from monsters, falls, drowning, falling into lava, suffocation, starvation, and other events. Players also have a hunger bar, which must be periodically refilled by eating food in-game, except in peaceful difficulty. If the hunger bar is depleted, automatic healing will stop and eventually health will deplete. Health replenishes when players have a nearly full hunger bar or continuously on peaceful difficulty.
Players can craft a wide variety of items in Minecraft. Craftable items include armor, which mitigates damage from attacks; weapons (such as swords), which allows monsters and animals to be killed more easily; and tools, which break certain types of blocks more quickly. Some items have multiple tiers depending on the material used to craft them, with higher-tier items being more effective and durable. Players can construct furnaces, which can cook food, process ores, and convert materials into other materials. Players may also trade goods with villager NPCs through a bartering system, which involves trading emeralds for different goods and vice versa.
The game has an inventory system, allowing players to carry a limited number of items. Upon dying, items in the players' inventories are dropped, and players re-spawn at their spawn point, which by default is where players first spawn in the game, and can be reset by sleeping in a bed. Dropped items can be recovered if players can reach them before they despawn after 5 minutes. Players may acquire experience points by killing mobs and other players, mining, smelting ores, breeding animals, and cooking food. Experience can then be spent on enchanting tools, armor and weapons. Enchanted items are generally more powerful, last longer, or have other special effects.
Hardcore mode is a survival mode variant that is locked to the hardest setting and has permadeath, which permanently deletes the world if the player dies. If a player dies on a multiplayer server set to hardcore, they are put into spectator mode.
Creative mode
In creative mode, players have access to all resources and items in the game through the inventory menu, and can place or remove them instantly. Players can toggle the ability to fly freely around the game world at will, and their characters do not take any damage and are not affected by hunger. The game mode helps players focus on building and creating projects of any size without disturbance.
Adventure mode
Adventure mode was designed specifically so that players could experience user-crafted custom maps and adventures. Gameplay is similar to survival mode but with various restrictions, which can be applied to the game world by the creator of the map. This forces players to obtain the required items and experience adventures in the way that the map maker intended. Another addition designed for custom maps is the command block; this block allows map makers to expand interactions with players through scripted server commands.
Spectator mode
Spectator mode allows players to fly through blocks and watch gameplay without directly interacting. Players do not have an inventory, but can teleport to other players and view from the perspective of another player or creature. This game mode can only be accessed within the Java or PC edition.
