A couple of years after Alpha Mission, SNK put out a follow-up of sorts — if not a direct sequel. (That would show up in the Neo Geo era!)
That game was Bermuda Triangle, and much like Alpha Mission before it, it’s a very creative and unusual take on a genre that, even as early as 1987, was heavily saturated with very similar titles of varying quality.
In order to stand out in such a situation, you need to do something distinctive — even unique. And, well, there are definitely a number of features in Bermuda Triangle that I haven’t seen attempted since!