If the game only has one achievement, the method of calculation becomes far less reliable. The OP list uses the most conservative estimate possible, but it could be off by a factor of 2, 3, 4 etcThat on the other hand seems way too high. The biggest VR title on the list (that costs money) is Job Simulator, and that was bundled with the Vive for a long time, and it's at 200k, both in the CSV and the barter.vg site, so H3VR selling 500k would be, whilst amazing, pretty headscratching too. I'm just going to chalk it down to H3VR's weird handling of achievements.