Brian Greenstone is one of few iPhone developers who have been extremely successful. Greenstone developed Engimo, a 3D puzzle game where you manipulate slides, bumpers, and other pieces to control streams of flowing liquid. Liquids fall from “droppers”, your objective is to move and rotate the various puzzle pieces to divert the flow of the falling droplets so that they can reach their target.

Greenstone’s Engimo has sold 810,000 copies of the game in only six months, netting him a cool $1.5 million in profit. Today, Greenstone did a quick interview with the Guardian and talks about his success with developing for the iPhone.

Greenstone says his company has entirely stopped developing for the Mac just over a year ago to entirely focus on building for the iPhone, comparing Mac earnings to merely “lunch money” compared to what the iPhone platform generates.