After I had sailed around my continent, I hopped off and finished a land bound corner of my map, and raced home before nightfall. I was low on supplies, so I restocked from the little that I had stored in that home and set off down through a cave system that I'd discovered before but hadn't had time or torches to really colonize.
An aside - torches are an interesting resource in Minecraft right now. They're the game's only ready light source, so if you're somewhere dark and you want to see at all, you need to place a torch on a surface. Also, monsters can only spawn in full or near-full darkness, so by placing a cover of torches around an enclosed space like a cave, you can make that space safe. The torches will burn forever, so that terrain is now 'colonized' for you indefinitely. Supposedly the infinite lifespan of torches is going to go away at some point for greater realism and danger, but for now, without any portable light source, you really need torches to burn permanently. Torches are easy to craft, though coal, one of the resources for them, is somewhat uncommon. What this adds up to is that explorations underground and at night are limited in their duration by the number of torches that you can make and carry. That can be a *lot*, but this adventure hinges on torches as a consumable resource.
I stocked up and headed down some small caves and lit their twists and turns until I broke through a narrow spot into a vast chasm. I not only couldn't see the far side, but I was on a cliff-edge and could see neither top nor bottom. To either side, off at a considerable distance, I could see lava-pools and lava flows that showed the chasm to be very large in all directions, with me probably near the top. I had found one of version 1.8's new "ravine" terrain features, and one that was completely underground!
My side of the chasm was rotten with caves -- good for exploring, but bad for getting to the bottom of the chasm, as I couldn't easily dig myself a path without a lot of backtracking as I emerged through the ceiling of a room. I explored and lit a few caves, none of which took me further down. I began to run low on torches, so I decided to stick to the ravine walls and to try to pick my way down. Soon I rounded a corner to find myself face-to-face with a cave spider, which leapt at me and in the battle knocked me off the edge.
At that point, I was sure that I was dead. You can't take much falling in any event, and the bottom of the ravine here was lava. As luck would have it, I fell halfway down and onto a lower ledge. That's when I realized that I had only a dozen torches left. I had to try to climb back to my safely lit area with a very small supply of light. I got an actual frisson of fear.
I hastily ascended, lighting only where I had to and hoping that mobs would not come pouring out of the side-passages I was leaving dark. In about 10 minutes of real-time, I found a chimney cavern that I remembered seeing from the top, and was able to carve a staircase around it and back to relative safety. Which is when I ran out of food.
Another feature in 1.8 which is very well designed is the food and hunger system. In earlier versions, food would raise your health, and health only declined by taking damage. In 1.8, you have a hunger bar. When it's full, you will slowly regenerate health; when it is empty, you will rapidly lose health; it runs empties over time as (I believe) a function of the intensity of your activity. Significantly, the hunger bar is only filled by eating food, and health is only refilled by being full and regenerating over time.
There are a number of interesting consequences of that balanced system, but the one that I was facing was the added simulated system of being deep underground and getting hungry. I started for home, and soon found myself in a cul-de-sac maze of tunnels. They were all well-lit, all familiar, but I couldn't find the cave that led out. Eventually, as hunger became more urgent a need, I found what felt like the highest point, and decided to dig my way straight up as far as my ladders would take me, and then to just dig-and-fill my way to the surface, hoping that my light and food would hold. I checked my map and saw that I should be safe and not emerge underwater.
I dug up, and ... hit water. After a brief glimpse of light, I was swept back down and had to return to the bottom to get air. What could I do? If the water was in an unlit cave, I had no more light to place. If it was on the surface, my map should have shown it. I was now running out of time, though, both real and in-world, so I decided to risk it. This could mean losing everything, including my hard-built map, at the bottom of a lake that I couldn't swim to, but I had to try. I furiously swam and dug up toward the light ... and emerged just before my air ran out ... in an overhanging pool on which I had built my house. I was home!
Just as the map and terrain changes worked together to make significant geography emerge in my previous adventure, resources, terrain, and mobs combined to make a real adventure story emerge. Running short of one resource, being pushed beyond my intended range, and then having to conserve my resources to return to safety created the common thread of events which form a meaningful story.