[3][4][5] The functionality of the library includes support for basic 2D graphics, image manipulation, text output, audio output, MIDI music, input and timers, as well as additional routines for fixed-point and floating-point matrix arithmetic, Unicode strings, file system access, file manipulation, data files, and 3D graphics.

[7] Released under the terms of the zlib license, Allegro is free and open source software.

When Hargreaves realized the platform was dying, he abandoned the Atari version, and reimplemented his work for the Borland C++ and DJGPP compilers in 1995.

As DJGPP was an MS-DOS compiler, all games which used Allegro therefore used DOS, attracting the enthusiast scene for that legacy system.

Current development is focused on the Allegro 5 branch, a complete redesign of both the API and much of the library's internal operation.