Agreed - a lot of testing and bug fixes to get 0.39 out, but not enough time to get much new in-game stuff for players to chew on.
Hoping to get the biome update (or at least part of it) in the next version: adding water, sand, snow areas etc.
Other half-baked features been working on in the past month: Creative Mode, enemies(?), fixing z-sorting (so that sprites are better layered and go behind each other properly when you're walking around).