Timeline of Hand-Held Game Devices

Atari Lynx

Atari Lynx

The Atari Lynx was released in 1989 by Atari Corporation and was a 16-bit hand-held console. It was the worlds first hand-held console that had a colour LCD screen, the system is also notable for its forward-looking features, advanced graphics, and ambidextrous layout, this allowed players that preferred left-handed controls to flip the console upside down and switch the side of the face buttons.
It had a MOS Technology 6502 CPU, and a screen resolution of 160 x 102 pixels. The console also featured an online capability, allowing you to connect to 17 other players. The console was originally meant to have games stored on tape but then were changed to be read off of ROM Cartridges.

Sega Game Gear

Sega Game Gear

This was the first hand-held console made by Sega and was also the third ever commercial coloured hand-held console. It was released in Japan in 1990 and released in North America and Europe in 1991. It's price at launch was $150.
It was a cartridge based console that had 8kb of RAM and 16kb of VRAM, with a Zilog Z80 CPU that produced at most 3.58 MHz of processing power. It was also based on an 8-bit Processor.
It's most popular game was easily Sonic the Hedgehog, Sonic is Segas most successful game charcter and has had many sequels, some good, some bad...
In total the console sold over 11 million units and was discontinued in 1997.

 Game Boy Color

Game Boy Color

The GBC was a big step forward in hand held gaming, with many popular games and many third-party companies willing to make games for the console. The GBC has been described as 'having a bit of something for everyone' as so many games were released on the console that it was easy to find one for many types of gamers.
The console used a Zilog Z80 CPU that had up to 4 or 8 MHz of processing power (two processor modes).  The screen resolution was 160 x 144 and had 32,768 palette colours available to the console and could have 10, 32 or 56 colours on screen, it could have 40 maximum sprites, 10 per line and each sprite having 4 colours. With 8MB of ROM, 32kb of RAM and 16kb of VRAM with a cartridge RAM of 128kb.
The all time best selling game on the GBC was Pokemon Gold/Silver, selling over 14.1 million units in total. The console had an 8 point D-pad with A, B, Start and Select buttons, power switch, volume slide and could use Infra Red to connect with other consoles.
One of the most praised things of the console was its long battery life, the console could have over 30 hours of game play using standard AA batteries.

Game Boy Advance

Game Boy Advance

Following the success of the Game Boy Color, the GBA also advanced greatley on what was possible with hand held Gaming.It was released in Japan on March 21, 2001; in North America on June 11, 2001; in Australia and Europe on June 22, 2001; and in the People's Republic of China on June 8, 2004 (excluding Hong Kong).
It had approximately 15 hours on average while playing Game Boy Advance games (also dependent on the Game Pak being played, volume setting and any external peripherals being used - e.g. a screen light). The consoles CPU was 16.8 MHz 32-bit ARM7TDMI with embedded memory. 8 or 4 MHz 8-bit Z80 coprocessor for Game Boy emulation, as the console was backward compatible so you could play all of your GB and GBC games on the GBA as well. It had 32kb of RAM and 96kb of VRAM (Internal to the CPU).
Its best selling game was Pokemon Ruby and Sapphire, selling 13 million copies as off 2004, man people seriously love their Pokemon!

PlayStation Portable
The PSP was made by Sony in response to the growing popularity in hand-held gaming. The original launch of the console didn't do so well, although the console was rather cheap, the launch titles weren't very good, a few ok games were released such as LocoRoco but it took a short while for the console to pick itself up and start to succeed. The console sold 71.1 million units worldwide to date, so you can see that the console quickly grew in popularity as prices lowered and more enjoyable games were released. The interface of the console features a D-pad, analod stick, 2 shoulder buttons, Sony's signature cross, triangle, circle, and square face buttons. The console also included a Home button and a button to change the brightness of the screen. The console also was the fist to use UMD's, which were developed by Sony and were a small Disc in a plastic case the you put in the console. It aslo used a Magic Gate Duel Memory Pro Card to save data on it, you could also save music, pictures, and films on to it and could also browse the internet on it.