AGI & SCI Defined

AGI stands for Adventure Game Interpreter, an adventure game engine developed
and used by Sierra on-line between 1984 to 1989. The graphics were low
resolution and blocky and the games only supported internal speaker sound (at
least on the PC), but at the time this was revolutionary. However, Sierra
managed to create some great games using it. AGI used a text-based parser
interface which was more limited than SCI.

SCI stands for Sierra Character Interpreter, an adventure game engine
developed and used by Sierra on-line between about 1988 and 1992. It made use
of EGA (320x200 in 16cols) graphics, and mouse and keyboard for movement. It
also featured a text-based parser, which interpreted sentences inputted by
the player and instructed the game to act upon them.