Harrier Attack Reloaded

Harrier Attack, by Durell Software Ltd, published by Amsoft, is an iconic game that is instantly recognizable by Amstrad users as it came bundled free with the machine. I remember spending many hours playing it with my dad when we got our first Amstrad, a CPC 464, back in 1987. I flew the plane and my dad pressed the space bar to bomb the targets. Many people have fond memories of growing up, playing this game.

Some are under the impression that Harrier Attack was written in the BASIC programming language. They may think this due to its slow speed, blocky movements and 8x8 character-sized sprites. But it is written in machine code. Its slow speed is due to the entire screen being scrolled one byte at a time. There are also program loops inserted by the programmer to deliberately slow the game down, presumably to make it easier for children to 'win' on the earlier levels.

As Harrier Attack is a fairly simple game, I wanted to see if I could disassemble it, to try to speed it up. The result is Harrier Attack Reloaded!