Minecraft wiki entry for Mechanics, associated text: Advancements‌[Java Edition only]: An optional progression tree that gradually fills as the player progresses in the game.
Achievements‌[Bedrock Edition only]: A system similar to advancements.
Experience: Players collect experience points from various sources, and can use them to enchant or repair items.
Game modes: Different ways to play and to interact with a world and its contents.
Health: Players, mobs, and some other entities have a specific number of health points (shown in a GUI gauge); when these are all removed by damage, a player or mob is killed, while other entities are broken or destroyed.
Healing: Players, some mobs, and some other entities can recover health points via various means.
Heads-up display: The HUD appears on screen while the player is in the game. It is superimposed on their view of the game world.
Hunger: Players have a partly-hidden stock of "hunger" points; they can naturally heal damage (at the cost of hunger) if their hunger meter is full or nearly so, and sprinting requires a minimum hunger level.
Food: Players replenish their hunger points by eating various food items.
Inventory: The pop-up menu that the player uses to manage items they carry.
Language: A feature that allows people to play in a language they prefer.
Skins: Custom textures on the characters that players can modify at their own preferences.
Emotes‌[Bedrock Edition only]: Emotes are a part of the character creator that allows players to perform animations.
Status Effects: Various conditions (good, bad, or neutral) with limited duration, which can be inflicted on players or mobs in an assortment of ways.
Third-person view: Allows the player to view the nearby environment from an "outside" perspective.