essentially went and added basic procedurally generated dungeons and a new weapon (the "rocket shovel").
the dungeons are generated on a regular grid, basically by partially randomly spawning dungeon chunks and having new dungeon chunks grow off of existing dungeon chunks (when new terrain chunks are generated).
as the the chunks grow outward, they replace voxels in the newly spawns chunks they grow into with their own voxels, and as more new chunks spawn next to these chunks, they grow into them as well.
currently, there are 16 types of dungeon chunk, most being variations on rooms and tunnels.
planned features are ladders or stairs between levels of dungeon and also occasional surface-level access.
the new weapon is basically just a rocket launcher with the behavior tweaked, where it has the special ability to destroy terrain even when most normal weapons have terrain destruction disabled, but with the actual damage to entities reduced.