I remember being a kid and negotiating with my grandmother, yes negotiating - She was never going to easily give up money for video games (especially if it wasnt educational).  I either needed some new grades to display or crazy chores to accomplish to get what I wanted.  I can remember very clearly planning to get this game.  I was not sure what its allure was (above the other games I had), especially where side scroller shooters were involved.  However, when I got it, I remember being hooked.  I loved the entire premise, the cool craft, the weaponry and customizability, especially the variable difficulty.  It was the same game I'd played in other instances, but not.  Perhaps games like this are what led to successful interpretations and advancement in flight style story telling as in Crimson Skies on the XBOX which is one of my particular favorites.