Handheld electronic games are very small, portable devices for playing interactive games, often miniaturized versions of video games. The controls, display and speakers are all part of a single unit. Rather than a general-purpose screen made up of a grid of small pixels, they usually have custom displays designed to play one game. This simplicity means they can be made as small as a digital watch, and sometimes are. The visual output of these games can range from a few small light bulbs or LED lights to calculator-like alphanumerical screens; later these were mostly displaced by liquid crystal and Vacuum fluorescent display screens with detailed images and in the case of VFD games, color. Handhelds were at their most popular from the late 1970s into the early 1990s. They are both the precursors to and inexpensive alternatives to the handheld game console.
The initial success of Mattel and Parker Brothers' entries spawned a wave of similar handheld devices which were released through the early 1980s. Notable among these were a series of popular 2-player "head-to-head" games from Coleco. Other games were miniaturized versions of popular arcade video games.
During the 1980s, LCD displays became inexpensive and largely replaced LED displays in handheld games. The use of custom images in LCD and VFD games allows them to have greater detail and avoid the blocky, pixellated look of console screens, but not without drawbacks. All graphics are fixed in place, so every possible location and state of game objects has to be preset(and are usually visible when resetting a game), with no overlap. Illusion of movement is created by sequentially flashing objects between their possible states. Backgrounds for these games are static drawings, layered behind the "moving" graphics which are transparent when not in use. Partly due to these limitations, the gameplay of early LCD games was often even more crude than for their LED antecedents. Some of the more well-known handheld games of the LCD display era are the Tiger series, and many titles from other companies were also popular, especially conversions of arcade games. New games are still being made, but most are based on relatively simple card and board games.
At the lowest end of handheld game sophistication, there is also the "miss/catch the falling objects" game. These games are controlled with 2 movement buttons, and sport a screen with a column of player positions, and rows of projectiles to animate towards the player. The player and projectiles could be any picture, from tanks dodging missiles to a dog catching sausages. This variety of game is cheap enough to bundle with a fast food meal.