I was waiting for somebody to post Convoy no Nazo. This game has probably some of the worst examples of fake difficulty and poor balance ever seen in a famicom game. That, and I'm amazed Ultra Magnus can somehow die in one hit.
It was followed by the (slightly less crappy, but still awful) Transformers : The Headmasters for the Famicom Disc System, which is just as unfair as its predecessor.