http://www.sega-am2.co.jp/ under Games, use babelfish.altavista.com to translate...

Okay so it is the official AM2 site (in Japanese)! It has a timeline of many of the AM2 arcade and home games and details the difference between Afterburner 2 and Afterburner 1 as follows:

1987.07 (ARCADE) - Afterburner - SEGA 1987

The 3d shooting game which reproduces the dogfight by the fighter plane to real. You board to the frame which makes the cockpit think, encounter to a considerable degree can taste the speed impression and the refreshing impression.

1987.10 (ARCADE) - Afterburner II - SEGA 1987

3 months, ' II ' " throttle lever " was added from the previous production, speed adjustment of the our machine became possible. The numerous enemy plane where you freely use the technique of rolling and the afterburner, et cetera the sweat the speed impression of grasping and, you attack in the hand and comes. The animal of speed of sound of the name, fighter plane, the dog fighting spirit which is unfolded in the skies!

so the difference is basically the throttle control.

Ice