Harvest Moon is one of my favorite game series of all times. But it was the 64 that made me fall in love with the farming simulation. Way better than the newer simulation games for the pc, or those that you can find on Facebook.
Graphics 9
Don't expect something like a Conker's Bad Fur Day graphics for this score. It deserves it because hey are how they should be. The game shows 3D environments with 2D pre-rendered cute sprites for every character, item and animal, and other stuff. They look cute, as they have to be. It was a nice jump from the 16-bits graphics, as they look more detailed and have more animations, even sprites that show you the face of the character when you talk to them. These were the graphics the game needed. But is better to notice the differences between the seasons, when you farm is full of snow and completely white.
Sound 9
I must say this: I love the music and sounds of the game. The music is enjoyable, changing every season. When you are new to the game, you should be asking yourself on the last day of the month "how will be the next season's theme". I love listening to my cows, sheep, chickens, horse and dog when they make their respective sounds.
Addictiveness 10
Easy as that, I've played many times Harvest Moon 64. I will make you picture this: You get the ending, where you get information about how good you did and in what you needed to do more. You enjoyed so much the game and you say to yourself: "I can do it better this time". That's me, and then I find myself searching for information on how to improve my game.
And for the record, this is the kind of game you say "5 minutes more", and then you find yourself 2 hours later asking to you why you didn't do your homework first.
Story 8
The game premise is simple, and it is shown on the game's intro, just like in the SNES version. Your grandfather died and his farm hasn't been cared for too much. You decided to take the farm going once and then the game begins. But that's not the only story, While you make friends and woo a girl, you'll start discovering their stories, you can even see romance going on between characters. Everything opens to you as you play and you notice every character own personality nicely represented.
Depth 10
Wait, how a game about farming can have a 10 on depth? Easy, you are not just farming in this game. Harvest Moon 64 is part social simulation, so you can go and try to become friends with the town folk, even get married, have a kid and be a good father and husband. The game is deep at some points, every character has their own favorite things, and others they hate, and discovering them can be tricky, because if you give them something they don't like, they'll hate you

. You can participate, in annual events in town, allowing you to gain prizes, and if you win an animal contest the animal's produce will worth more, and maybe becoming closer to the people.
You have collectibles too, find all the recipes (which you can't cook, but are necessary for a perfect ending ¬¬) , photos through events and power berries that will make you stronger, allowing you to last longer in work.
Difficulty 6
Harvest Moon is not a hard game. In fact, you can make it as challenging as you want. I can say that after seeing people trying to achieve a perfect ending, which is hard and you require every second the days lasts in the game. If you want to take it at your own peace, it's not a difficult game at all, but there are some problems here and there.
The main problem is the time you have in one day. Sometimes doesn't seem to be enough, you can finish a week in one hour or less, which is fast. The second problem is how some of the animals work. This was fixed on later installments as you can pass through or jump over the animals, which could get you to some frustrating... STUPID HORSE, GET OUT OF THE WAY!!!! (Resetting the game because I got stuck situation). The last one is that it is easy to fail where you are trying to do something, making it a waste of resources because if you try to give something to someone you might throw to the ground and loose it because it is difficult to know if you are on the right position.. or he just moved when you pressed A

Overall 9
I don't think Harvest Moon 64 is a must play for HM fans. I believe it is THE Must Play Harvest Moon of the series. It's nice, even with some problem there and here that can get frustrating but are really easy to fix (Really, you can avoid them easily). It's fun to play, it is nice to talk to the character's personalities and fun fearing you rival in love would get married with the girl you are trying to give the Blue Feather to marry. Just take you hoe and watering can, because it's time to grow some turnip!.