The three ages of darkness have finished, now a golden one starts and with it a new way of living through philosophy and virtue. A call is sent to summon a new kind of hero, one that does not triumph through the sword, one that can become a spiritual guide and help others to walk the path, an avatar of the virtues.
For the first, and last time, outside the continuations and as far as I know, a game had a serious philosophical background. It is not confusing and complex, nor it as usual silly and simplistic, as you will discover as game advances. Nobody will explain you this philosophical system. It will be necessary to travel around the world and speak to nearly everybody to gather clues and find how this system works. Everything will have one, even the objects you will have to recover and the places you will visit, so you also observation will be required to complete this puzzle.
All of this can be done in the order you wish, there is no linearity. You may even go to the last part of the game quickly with a bit of skill and luck, but you won't be able to pass the tests that will grant the avatarhood, as there is more than knowing the virtues to be able to finish the game, you must act according to them.
This is not too hard, you can get many hints about what to do, and as long as you can resist temptations, act with some common sense and fight, fight too much, you will quickly be able to get the eight partial avatarhoods.
Only one of the virtues gives a true problem, along with the hordes of monsters which will attack you continually outside the cities. As soon as you are engaged in combat you should fight until the enemy's death, or the death of some comrades, or fleeing will be a coward action, so when travelling you will have to fight continually your way, which can get quite tiresome and boring.
Anyway, the fights by themselves are not bad done. It's turn based, with some variated equipment, as the halberd wich allows you to hit twice as far but not at close quarters, or the flaming oils which create a wall of fire. But there is the problem of the subjugation the character classes impose you.
Another point is the magic, which is taken with at least a bit of seriousness. In this case what puts it closer to a mystical science than psychical powers that can do whatever they wish are the reagents. Each spell is a combination of the eight magical reagents, some may take only one, and some may take a bunch of them for the mix. This puts limitations to your spell casting, as they have to be prepared previously to their use. These reagents can be, normally, bought in some towns, with varying prices, but a pair of them, the two more powerful, will require a quest.
This brings another lack of the game, there are few secondary quests. It may not be much of a lack as the main quest is composed of many shorter quests, and those few secondary ones aren't short anyway, they will require you to travel and explore as much as the other ones, and their reward will be much more direct and material, a new object or tool to help you in your quests.
But they won't be more useful, normally, than the tools you will get more easily and use more often. 'Magic' keys (lockpicks) and gems that show you a map of your surroundings, and adding to this the ways of transportation such as the ships and horses, helped by the mystical moongates which connect locations marked by the twin moons phases.
This game is what resulted of trying to solve the main problems that RPGs had twenty years ago. Sadly, they are the same problems that plague the more popular ones of today, and none have tried the same solution and story that starting with this one made popular the series, being a good guy with a reason and method.
Note: The two game manuals contains important information and background story, I recomend downloading it in a manuals web previously to playing the game.