Last commit involved laying the groundwork for in-game flight. Not in the sense of moving around several Z-levels above ground, because there are no Z-levels in this game¹, but in the sense of passing over fences, water, and other things you can’t walk on.
It also involves a bit more strategy in that a walking creature (unless tall enough) can’t hit a flying creature in mêlée, but a flying creature can hit both other flyers, or divebomb a walker. Long-range attacks are fair game, of course. None of that has been implemented just yet, but that’s basically what’s planned.
The only problem is that laying all this groundwork changed the board format. But there’s already a bunch of breaking changes since 0.1.14 and the game can detect old, incompatible saves, so all’s well.
(¹: The dungeon generator has a sense of Z-depth but the individual boards are still flat.)