Alpha Mission 2 is actually about equal to Ghost Pilots in terms of speed. The shooter engine is also about the same. But I'll warn you, as a shooter fanatic, AM2 is very BORING, unrewarding to me, and I often die so much, I can never carry powerups for long. So i am relegated to the typical 'pea shooter' weapon, which makes the game BORING. The only thing that saves it IMO is the music, which is actually fantastic. The bosses were decent too.
IMO, the game is only worth buying for collector/complete purposes, and not to have a good time with. As a fan of Alpha Mission 1 on NES, I was disappointed.