As the inlay notes say, "Will you overcome the warlock's evil creations? Will you survive long enough to create the golden key that is needed to free Princess Mertha? Probably not." Seems fair enough to me.
It's not as sophisticated as the original - or indeed as original as the original - but it's a jolly little shoot-'em-up with some entertainingly wacky palm trees and a couple of weapon systems you won't find in many air force bases.