Air Duel

Irem M-72 system hardware

Main CPU : V30 (@ 8 Mhz)
Sound CPU : Zilog Z80 (@ 3.579545 Mhz)
Sound Chips : Yamaha YM2151 (@ 3.579545 Mhz), DAC (@ 3.579545 Mhz)

Players : 2
Control : 8-way joystick
Buttons : 2
=> [A] Gun, [B] Guided bomb

Air Duel was released in June 1990.

Several music pieces from this game were recycled for others games from the same musicians:
The mission 1 music was recycled and remixed in Gun Force II (Stage 2 part 1).
The mission 2 music contains a synth solo (after 32 seconds) which was performed with a sax in "Metal Slug 2 - Super Vehicle-001/II" (mission 3).
The mission 3 music was recycled and remixed with electric guitar in Metal Slug 3 (mission 1, underwater way).
The mission 3 music was also recycled and remixed in Gun Force II (Stage 2 part 2).
The mission 4 music was recycled and remixed in Gun Force II (stage 1).