Dungeons in the gameworld will be sources for looting and leveling. There will be hundreds of ways to level when the game is 100% finished but for now its dungeon diving. This means youre going to have to deal with puzzles, traps, monsters, boss fights and everything expected of a D&D style dungeon (including the loot)
Every dungeon will have sprawling "top level" zones, these are essentially level 0 areas as a way to introduce you to how the dungeon will operate in the lower areas.
Dungeons are color coded a Bright Green to tell you its a dungeon, normal caves, burrows and small "mini" dungeons will be colored Brown
Most dungeons will not be well lit, so if you have trouble seeing as a real life disability or a handicap just know a head of time about this and be sure to stock up on torches, candles, lanterns, or use light spells that is why they are there.