Wow, what a classic game. I remember when my Dad first brought home an Amstrad it had a bundle of games and Harrier Attack was among them. One of the best. It's a simple game in simple graphics. Fly along the top of the screen, bomb what's beneath you and shoot enemy planes out of the sky. Like I say, simple, but absolutely bags of arcade gameplay. Gamers may find it a bit simplistic nowadays but back in the day this was cutting edge game, and for my age pretty hard too.
Give it a try, it deserves no less.
Graphics: For its time, pretty good, planes were identifiable, targets were identifiable, bombs were bombs and missiles were shots, sure it was simplistic, but that was all you needed back then.
Sound: From what I recall Harrier had good music. The sound was pretty intense with satisfying explosions every time you blew something up.
Gameplay: No story to speak of, games didn't have them back then, just a side scrolling piece of arcade action where you survive as long as possible. Bomb as much as you can. Keep going for as long as you can.
Overall as you can see there's not much too it, yet there was something about it which kept bringing me back to this
game (along with the Galactic Plague, another bundled arcade game) and bear in mind that games back then took 10 to 30 minutes to load and newer games always pushed the boundaries. Yet I still came back to this. Because it was a grade A game.