True to its tagline: Strange, funny, and heart-rending.
Mother 3 is in a way, the perfect sequel. Many games try to retread the ground their prequels already went over, becoming stale, or try something radically different, alienating the fanbase. Mother 3 went for a more reasonable route. This game follows the logical extension of the last games themes.
The theme this game is corruption, and the growth of strength despite misfortune. Spoiling any part of this game would feel like a sin to me, but suffice to say that the story has excellent pacing, not drawing things out with too much unnecessary dialogue, a trap many RPG's fall into.
This game isn't all story however. It's gameplay is quite similar to Earthbound's, with on-screen enemies a la Chrono Trigger, and first-person fights similar to Dragon Quest. For the most part, it is just a well-designed battle-system, with good balancing throughout so it doesn't seem too hard or too easy, but it does have one thing unique to it.
A rhythm system. Unlike those you might know of from Guitar Hero or Rock Band however, this one is *hard* The games eclectic soundtrack loves smacking you with insane time signatures, and the window for getting it right is extremely small. Difficulty would be an issue, except for that it just adds damage to regular attacks, you don't really need to use it.
Overall, I can't find anything in this game to complain about. The soundtrack isn't quite as good as Earthbound's, but quite fitting, and strong in its own right, and it expands on every other front. A must-have for sure, and the fan-translation makes that a possibility, go get it!