That reminds me...why is Granzort considered the sequel to Keith Courage In Alpha Zones? The games are NOTHING like each other. Sure, Granzort features a mech-like character who wields a sword...but he also wields guns and whatnot too. Also, in Granzort, if you get hit once, you die...Keith Courage had a killer liferbar that was hard to deplete unless you were up against some of the more powerful bosses (like the one in level 4 or the final boss in particular). The only similarities between the two games are the mech concept and the company who produced the games...the games are otherwise nothing like each other in any other way and it's a tremendous stretch to call Granzort a sequel to Keith Courage...just as it's still a stretch to call Super Mario Bros 2 (the US one, not the Japanese one which actually WAS a sequel) a real sequel to SMB.
I *think* all of these games (Keith Courage, Granzort, an NES and even a GB game as well... see
this link) were all based off-of a popular Japanese anime. So, in a loose sense, all of these games are related. Beyond that, I'm not sure of any similarities (i.e. developers, designers).
famicom:
Majin Eiyuuden Wataru Gaiden
Granzort strips away the "overworld RPG" stages and is more "serious" (aesthetically, atmospherically) than Keith Courage. I agree, it's a very loose connection, but I can see it. VERY LOOSE