It shocks me, why are RPGs now a days not this good? I'm not even saying this from nonstalgia... I HATE nonstalgia.
Combat:
It's simple, it's clean, and effective. You don't have a hassle in combat, and battles go by really quickly if fights aren't life threatening. They even make you auto win fights you easily overpower, so you don't need to go into a combat screen. Enemies don't randomly appear annoyingly, they're on the grid from the moment they come on screen and you see what you're fighting before you go into combat screen. If there's multiple enemies you're fighting, then you see them all on screen before you fight. The backgrounds are trippy and pleasing to watch, with large verity, and boss fights are rather bad ass and often comical as well.
The combat also has a sense of speed to it. when you get hit for like 300 damage, you watch the counter move your health down from where it was to 0. You have time while it's counting down to heal yourself, and this adds not only the speed to flip through menus quickly, but the forgiving-ness of not taking all your damage in 1 second.
World:
You know what pisses me off? When they use the generic "dragon fantasy midevil" setting. Hell, even the futuristic fantasy setting is getting rather generic. What setting is this in? A perfectly modern looking (for the time it was released) world, with a lot of comedy and imagination around the world. The verity is huge. You've got your haunted zombie infested city of threek, the northern wintery place, oddly named winters, with it's hot beach counter-part, summers. The huge city of fourside which I'm sure you've all seen from super smash bros, your average town onett, and just a large ammount of humorous places like the saturn valley, and the happy happyvillage.
Story:
This sounds rather simple... a meteor hits the top of a large hill north of onett, and you wake up. Having pokey and his brother, and your dog following you to go check it out, when suddenly a bee comes out and helps you fight an alien that's standing in your path. Pretty much you stand by doing 1 or 2 damage to it while the space bee does all the damage and puts you behind an impenetrable shield. The bee dies later and you basically set out to save the world from aliens. It may not have too many dynamics story wise, but after fighting so many damn goblins and black knights, fighting off an alien invasion in an rpg is hugely refreshing.
Characters you meet never seem completely forgotten about next scene of the level, but not to an overkill to where you only meet those people. Making sense? I figured not, so lets just move on.
Music:
Can't blame any rpg really for music, they always try to incorporate a great fitting soundtrack. Earthbound just does it to a great point. Everything suits the mood really well, right down to the scary and odd cult of the blue painters. Sound is never something I have complaints about accept on the worst of the worst RPGs.
Overall:
Earthbound is sadly the best RPG I've played in a while. It's refreshing, it's got a unique story with humor that helps without overpowering the plot. It's epic, without overkilling the idea, and the overall verity and perfection of each section makes this one RPG I've recommended to countless people now. If people believe RPGs are being ruined today by ancient turn based combat or that traditional RPGs move too slow in story, no that's not it. The problem is, people aren't putting the details that matter in, which is functionality and originality, something earthbound has mastered. RPGs that fail are those with an over done story and a those that rely too much on number crunching stats and too little on making the game fun for people beyond the hardcore RPG crowd.