The game starts out as a single player survival dungeon game. As things are now the player can choose to play a mage, a warrior or a rogue, maybe a priest. Nothing special sofar. The core features are a rune magic system and a crafting system.
Each class has a special magic talent, the warrior has the ability to draw energy from his body, the mage has the ability to draw energy from the world and the rogue has the ability to get his energy from the world too, but only a fraction of the power of the mage.
To use magic you need to bind a rune. Runes can be found in the dungeon or looted from npcs. You are only able to bind a certain number of runes concurrently, similar to guild wars skills. The talent of the classes will define which runes are usable. A warrior must touch a target (through a weapon) to tranfer his energy, whereas a mage don't need any phyiscal contact. All classes has something in commmon. Drawing energy is hindered by metal armor. So, only the warrior is able to wear metal armor without sacrifing his ability to use magic runes.
A special case is the rogue. His abilities are by far not as powerful as the mages abilities and he can't wear any metal armor as the warrior, so he needs to use crafting for his own benefits. So rogue magic often needs ingredients.
Crafting will play a major role, all classes will benefit from crafting. The crafting system represents the only skills in the game, there will be no other. On the other hand the runes are similar to "skills" found in other RPGs.
The dungeon dwellers will mostly consists of animals and monsters. At the current stage there are spiders and "flying" worms. There're a lot of different varients of each dungeon dwellers. Each dweller has its own indiviual behaviour and it is not safe to say how it will react to you. Monsters will watch you, flee, or attack. They learn about the dungeon, about where they encounter danger or traps, and they will tell others ! They will loot other monsters, they will collect resources, they will eat and they will relieve themselves (leaving important resources).
So it might be a bad idea to attack a tame monster and let it flee, you could encounter its great brothers if you keep staying there. Some monsters are important to produce certain resources, other monster might help you fighting other monster hives.
Each monster is part of a hive, each hive will spawn new monsters and it will react to danger. If you or something else will kill every monster of the hive, the hive will react to the new danger by spawning more powerful dwellers, until the hive itself gets destroyed or runs out of resources.