The MineScape user interface is a heavily tweaked version of the Minecraft UI.
HotbarEditUnlike in Minecraft, hunger isn't currently used. Eventually, it will be used as the Prayer bar, and the oxygen bar may be used for cooldowns & progress of a current task (say, smelting a bar).
The blue experience bar above the hotbar is used to display progress in the current skill. For example, when cutting down trees, the bar will display the level of Woodcutting and the player's progress to the next level.
InventoryEditThe inventory's UI is heavily based on Runescape. The four editable rows are used to store carried items. The armour slots along the left are used for helmets, chestplates, platelegs and boots.
Quick AccessEditThe Quick Access menu takes up the spaces normally used by Minecraft for portable crafting. In this menu, you will find buttons for Skills, the Spellbook, the ability to switch stance, a currently non-functioning Quests button, and a Settings menu (which does not exist yet). Simply click on the menu you need, and press your inventory key (usually E) to exit.
When smithing and performing similar tasks, a custom UI is displayed.
Read more on this on the Trading page.
Conversations with players and NPCs are shown here. Currently, the player's level displayed alongside their name.
The skills sidebar is fastest place to check your progress summary on all skills. These are displayed from highest to lowest.