The graphics aren't bad for when it was made, and even though the characters aren't very detailed, their faces are still pretty expressive. One thing to note though, Suikoden III does not have any movie cut-scenes, or any voice acting for that matter.
Music doesn't really stand out, but it's pretty decent. There are one or two songs that I really like, and the game opening is the best I've seen of any game so far.
The battle system in this game kind of reminds me of the later Grandia games. Characters move in the battle screen according to their actions, and casting magic requires time, so depending on many factors, it can be cast instantly or take up to 2 turns. When a character (or enemy) is casting a spell, the action can be canceled by physical attacks, so that can be tricky as well.
Also, character formation consists of 3 pairs, each of them moving together. Because the character at the front of the pair is more likely to be attacked, and some characters are not really compatible due to their movement speeds, pairing up can be quite strategic as well.
The strongest point of the game is by far the story. What started as a simple land boarder dispute quickly escalates into something much larger and sinister. However, just like the other Suikoden games, the evil ones aren't truly evil; they are just doing what they believe is the best for everyone.
Usually I find tracking the 108 stars of destiny (the recruitable characters) to be a bothersome task, it isn't as bad in this game. Sure, I had to use a guide to find them all, but there aren't really any that will disappear forever after certain points in the game. So basically, even right up to the final dungeon, you can still roam around and recruit anyone you are still missing.
Even though I really enjoyed the game, what bothered me the most was the amount of back-tracking I had to do. The world map is set up like roads connecting each location on the map, but the catch is that no matter what, you can't pass each location to get to the next unless you physically enter it and go through that way. Therefore, until you get the option to teleport anywhere in the later half of the game, you will be spending a lot of time traveling through places you've been in already over and over again. Thankfully, most of the areas consist of only a few screens, so the walking and monsters encounters are minimal.
To sum everything up, Suikoden III is definitely more fun and exciting than it looks. The characters are really likable, and the plot is excellent. If you can bypass the boring bits here and there, you'll find that in the end it's all worth it.