Also some Games Producers sometimes displayed the HUD in another Graphic Mode, this allows to display a good 16 colours in the Game's window while the HUD use the highest resolution of Mode 1 to ease the display of informations.
The choice of HUD stye depends of the choices made with the game itself.
Vertical scrolling shooters often get a vertical HUD, Horizontal Shooters a Horizontal HUD.
The presence of scrolling also impose HUD technics.
A frame for exemple is often choosen when the game has no scrollings, yet not always. Programming evolved a lot in this field and Shadow of the beast display a huge graphically heavy Frame (wich is in fact a waste of tiles...).
==Horizontal HUD==