The impressive part of the NES was its picture processing unit, which among other things finally delivered on an arcade-like experience at home and gained mass appeal in the process. For the time it was considered quite an advanced chip in its price range. The other extremely clever thing Nintendo did with the NES was to put the video bus on the cartridge, and this enabled them to expand the console's apparent capabilities by adding new features to game paks. This helped to keep the NES competitive in the market for many years.