This is progressing very well. All the smaller details throughout the piece are very powerful in terms of adding depth. The best art comes in two forms: that capable of telling a clear, complete story and that designed to allow the audience to take from it what resonates with them, with this drawing being a strong example of the latter. I definitely like the direction that this is headed in and look forward to seeing it once it is finished. I hope that you keep the contrast of the mass on the left breaking into the openness on the right as it really helps to convey the idea of motion and change, suggesting that there will be something new to see at every glance.