It is a part of the Phantasy Star series of games that begun in 1987. The game has been followed by Phantasy Star Online Episode I & II
The game itself is a simple hack'n slash type Role Playing Game where you slay mosters, level up, buy new equipment etcetera. PSO differs from many previous games of this genre by offering a real-time, rather than turn-based approach to combat - and seamlessly integrating this with the exploration/plot development aspects of the game.
Communication between players is achieved via a combination of direct 2-line text entry, 'Symbol Chat' and 'Word Select'. As PSO online servers support international co-operative play, the 'Symbol Chat' and 'Word Select' features encouraged players to attempt communication with others, regardless of language.
'Symbol Chat' allows the player to define a collection of symbols within a speech bubble, in order to convey an emotion or simple instruction. These symbols could then be invoked via a player-defined shortcut, or accessed via an in-game menu.
'Word Select' acts as a limited phrasebook, allowing sentences to be constructed through a hierarchy of menus. Once complete, a sentence is automatically translated into the configured language of other nearby players, thus bridging the language gap encountered in cross-cultural multiplayer games.