MOTHER (EARTHBOUND ZERO) / Nintendo / NES
It pains me to say it, because I am a huge fan of the series, but the first Mother game is basically a crappy alpha version of Earthbound. The story and characters are basically just a less developed form than that of the sequel. The game balance is atrocious, being as grindy and time-consuming as the worst of the Dragon Quest games. The contiguous overworld map is a nice touch, but it doesn't properly delineate between safe areas and areas where you can be attacked, and talking to innocuous-looking people in an otherwise non-threating town sometimes throws you into tough battles out of nowhere.
There are things to like about the game, but they just get buried under the difficulty and the tedium of repetitious combat, and the general directionlessness and sparseness of the story. Also, if you've played through Earthbound before, you've seen a good 60% or 70% of this game's ideas already. It doesn't really seem to "hook in" to the Earthbound plot except in perhaps the most cursory of ways, and also possibly introduces contradictions, so if you're looking to it to enhance your love of Earthbound, you might actually be disappointed by it.
I just think of it as an early "practice" version of Earthbound, really.
* Gameplay Video
* Japanese TV commercial