I recently beat Earthbound for the first time, I have played it before, but went through a point of no return without being prepared and couldn't defeat the end boss.
For a relatively late SNES game, the graphics are primitive, almost to a fault. The graphics are very similar to previous game in the series, Mother on the NES. in the same style of classic Dragon Quest games, in battle your group of adventurers isn't shown at all save for the boxes that display their health counters and status. A psychedelic background and any enemies you happen to be tussling with are the majority of what is shown. I'm not quite sure where they were going the backgrounds, as they generally don't fit the area that your combat is taking place in. Characters on the overmap generally consist of sprites that have only 2 frames of animation and are merely flipped when changing direction. This becomes especially evident when a bus with writing on it turns around, leaving the writing backwards.
The actual gameplay is a pretty standard Japanese RPG fare, again very similar to Dragon Quest. Though there are still a few new, good ideas here. There is a rolling HP counter, making it so that when you take damage in battle it doesn't immediately subtract the damage from your health. The counter rolls down slowly enough for you to get a chance to react. If you're dying and manage to heal yourself before your HP reaches zero, you'll be just fine. The main healing items in the game are various foodstuffs. When you eat food, and have the proper condiment in your inventory, it will add a healing bonus to the food automatically. You don't randomly encounter enemies on the world map, instead they are seen walking around, and can be avoided entirely. Some enemies can even be snuck up on for a tactical bonus at the beginning of battle. Also, there are enemies in towns, normally a safe haven from any danger. Some of the hostile town inhabitants are visually similar to the friendly townfolk, so you have to be on your guard.
The big draw of the game for me was the humor. There were a huge number of times when I was playing that the game made me laugh out loud. It compelled me to do something that I rarely do in a game, to talk to everyone, just to see what they would have to say. One particularly humorous group of bosses are the 5 Mole Guardians who all claim to be the third most powerful of their group. They also have "No. 3" written behind them, in case you didn't get it when they told you before. Even when the story takes a darker turn, it still comes off as humorous. One thing that I'm not sure if it is supposed to be comical or not, is how the band in the game "Runaway Five" has 6 men on the stage while they're performing. Part of their name comes from the fact that there are 5 men in the band, and the elusive 6th man disappears whenever they aren't playing music and you have the chance to actually talk to them.
Earthbound is an amazing game. It honestly didn't seem like much when I first started it, but after I gave it a chance, it turned out to be a wonderful experience.