More Japanese (going for N3 in December) . Android game programming (iOS is apparently more profitable, but Java aligns better with my day job and lack of Apple devices). Possibly some deep learning.
After learning casually for over 3 years, I'm going to finally give the JLPT a try. I actually did a practice N4 test and the grammar was easy, but vocab is what really held me back
https://news.ycombinator.com/item?id=14647413