I would be very interested in some sort of summary how this HN post increased your sales.
Seriously: we (Blade Polska s.c.) have been through this also. We did everything according to common marketing wisdom about Tap4Two (even the landing page! [1] and real-life video [2]) -- it concluded in 10-20 sales each day. Mostly on the German Store.
We're planning runnig a facebook campaign targeted for Germans, spending all the revenue game has made so far. We will share the outcome for sure.
Your game looks like a lots lots of work with 3d engine, very impressive. What framework did you use?