As someone else pointed out in the replies, these seem to only count physical sales as we would see more from steam on that list. Regardless, I'm glad Demigod is getting the recognition it deserves. So far I've managed to get 10 of my friends on this game, and with the annoucment of community modding being added summer (patch 1.2), I can now go ahead and confidently push the rest of my friends to pick this game up.
See Frogboy, no need to worry. Go ahead and green light more updates and fund the heck out of this game 