N-Gage GD is a handheld console released by Nokia in 2004. As its predecessor, Nokia N-Gage, is a combination of a gaming console and a mobile phone. Nokia N-Gage GD runs the same edition of Symbian OS like its predecessor, even when Symbian 7.0, a newer version was already used in several smartphones.
With N-Gage QD, Nokia fixed some of the known problems of the classic N-Gage. The microphone and the speaker re-located at the front of the device. Cartridge slot relocated also at the bottom of the console. Probably in order to minimize production expenses - lower the price - and making the device smaller, the MP3 playback, FM radio reception and USB connectivity were removed. However, MP3 format was still supported with the use of a third-party software. Also USB connectivity replaced with Bluetooth or a separate MMC card in order to transfer songs and other media files. The only replacement in the controllers were the replacement of the original five-way controller (four ordinal directions and a center "click" or confirm) with a simpler four-way directional controller and a separate "OK" button with a check logo. Lastly, the N-Gage QD isn't supporting the three GSM frequency bands 900/1800/1900 like its predecessor. Instead, it came in two dual-band variants, one for the American market and another for the European and Asian markets.
In 2005, in an attempt to prolong the life of N-Gage, N-Gage GD Silver Edition was released, which is essentially an N-Gage GD device. The only difference, except the cosmetic changes, is the replacement of the two specialist gaming buttons (5 and 7) with standard keys.
Lastly, N-Gage 2.0 (or N-Gage Next Gen or simply N-Gage service) is a mobile gaming platform from Nokia that launched in 2008 and was available for several Nokia smartphones running on S60 (Symbian) OS.