From now on, some of the game data files will be put inside of one big file and thus made available for developers (that is, me) only. I strongly believe that it is essential for a roguelike game to keep some of game's internals in secret. Now I will be able, for instance, to create quests that would become a lot easier of one could take a look at the script files.
That change has at least one undesired side effect. The game is not customizable anymore, not to the level it used to be. However, I don't think it's that important for a roguelike. All in all, most of the few really successful games of that genre were not customizable and none of them were mods (as far as I know). Apart from that, I will provide a new mechanism of customization in the future.
Of course, the protection mechanisms for the Big File are quite easy to break if you know some assembly... I hope that nobody will actually attempt to reveal Untitled's secrets.
As of the other changes - some nasty surprises await your character. They might break leg or even completely lose a limb in fight, but don't worry - a skilled doctor will help you (at least if you have enough cash). The character might also fall sick. There are currently two kinds of sickness and several more are to come in future versions.
You will also have an opportunity to explore a new dungeon. This one is stored permanently, but new monsters will be generated from time to time, so you'll never be able to clean it out completely. There are few NPCs living in the dungeon and some new quests as well.
The complete change log:
Have fun!