Amiga Blitz Basic was originally developed as commercial software under the name of Blitz Basic and then Blitz Basic 2 by Simon Armstrong and Mark Sibley of Acid Software in New Zealand. It was later re-released as freeware under the GNU General Public License. More recently Bernd Roesch and others of Amiforce have continued development of the editor and compiler, under the name AmiBlitz.
AmiBlitz has continued to grow and evolve, adding many features that allow for more modern coding styles and techniques while retaining compatibility with the original Blitz Basic. For example, a set of "Include" files are now included with the AmiBlitz distribution which extend and improve the functionality of AmiBlitz by offering many useful functions and system-friendly alternatives to the older built-in commands. These files include support for most common dos.library functions, intuition functions, AHI support, graphics functions with 24-bit colour support and so on.
The AmiBlitz IDE has also been improved and offers such features as context-sensitive help for Include functions, variable and struct browser, syntax reference browser and so on. However, this means that the AmiBlitz development environment has higher requirements than the original Blitz Basic environment on which it's based, so for developing on an unexpanded Amiga, getting hold of the older Blitz Basic 2.1 might be simpler.