Ive been back to work in the last few weeks, after a longer-than-usual Christmas and New Years break, and Id like to share all the cool stuff that I worked on! Z-levels, which essentially mean building your dungeon over multiple floors, are probably the most requested feature in KeeperRL of all time. Ive been resisting them mostly due to lack of a good vision on how they would work with the rest of the game. They obviously increase dungeon building possibilities, but also make the game more complex. KeeperRL already features a decently sized world to explore horizontally, so how would vertical expansion complement it? I gave it some more consideration recently, and realized that Z-levels could solve a lot of the mining progression problems:

• Its easy to place guarding enemies on a subterranean level, and the player will easily understand that these enemies will attack if you mine there. No more confusion why you got attacked by ants or adamantine golems.
• Its common sense that enemies get more difficult as you dig deeper and deeper, and you cant accidentally engage an enemy thats way too strong for you.
• New Z-levels can be added as you dig, which means an unlimited supply of minerals, at the cost of having to fight stronger and stronger enemies.

The great thing about KeeperRLs source code architecture is that it has supported multiple levels since the very beginning, just that your dungeon could only be built on one level. A basic implementation that allowed multiple-level dungeons took me only a few hours!
After all that, there has to be bad news of course, and its that there are some limitations. First of all, right now, the game only supports up to one staircase between two levels. This is limited by the current pathfinding algorithm. Secondly, due to memory usage, the subterranean levels will be significantly smaller than the ground level. These are not set in stone, of course, so depending on your feedback, I can work on removing these limitations in future updates. There were also other, smaller features that I worked on. Ive committed to advancing the AI in this update, and the first improvement is that creatures will try to organize, and attack enemies in formations to avoid being picked out one-by-one. Healers will attempt to stay in the second line and tend the wounded.
To further improve combat tactics, I replaced 8-directional aiming with free aiming, so you can fire missiles and cast spells at anyone, as long as nothing is in the way. This should make archers and spell-casters more relevant in open area battles, especially when theyre controlled by AI. Elves are going to be very deadly! (and the interface is also prettier and more clear)
I dont have any plans or promises for you yet as to when Alpha 27 will be out, and if you are interested in hearing more about day-to-day development, I invite you to join the official discord server, where Im very happy to talk to players and share updates almost every day.