I know its not really my postion to ask. But I would like to know which features have already been coded into the codebase of v0.4.
The latest release, v0.3.8, is nearly up-to-date. Ship parts and hulls can be defined in text files, and added to designs in the GUI, and then those designs can be built if all the parts are available, though various details of this still need to be implemented. The design GUI is progressing, and can be seen in some recent screenshots I posted. Drag and dropping parts into slots basically functions, but can't actually be used to do designing yet. The initial test droplists do still work, though. The actual battle engine isn't very far along yet. Prep work is ongoing. If we had enough done to atually have battles of a few ships, you'd have seen posts about it by now.
Note that you can follow development progress by watching the SVN commit logs on sourceforge.