Dynasty Warriors 3 was one of the earlier Dynasty Warriors games, therefore, it wasn't as advanced as the Dynasty Warriors games today.
Dynasty Warriors 3 was made back in 2001, and it has most of the characters that Dynasty Warriors 5 has. Some characters, like Xiao Qiao and Da Qiao were in Dynasty Warriors 3 but not in Dynasty Warriors 4, but they reappeared in Dynasty Warriors 5, which is the game in the series that has the most playable characters.
Dynasty Warriors 3 was the first in the series to introduce a two player mode and numerous other improvements over Dynasty Warriors 2. New stages, characters, weapons, attacks and music are introduced providing a completely new experience to a player that has played Dynasty Warriors 2 before. The gameplay engine and the graphics engine have also been updated, providing higher quality environments, textures and general overall graphics. Only one expansion was released for the game, Dynasty Warriors 3: Xtreme Legends and it was the first in the Xtreme Legends series.
Extra Fact: This was the only game in the whole Dynasty Warriors series in which Nu Wa appears. Nu Wa was a female warrior who was the sister and wife to Fu Xi. However, she was cut out after Dynasty Warriors 3 and hasn't appeared since (although she did appear in Warriors Orochi 2, along with Fu Xi).