Master Of Arena took the Arena set up, which was an optional feature in Project Phantasma and made it integral to the game’s plot. In addition to playing missions to advance the storyline Arena matches were also requisite to advance the plot. Like Project Phantasma before it Master of Arena allowed players to import save data from previous games and allowed them to carry over parts and credits to help them when starting a new game. Master of Arena was the first AC game to be split onto two discs with the first disc consisting of mission and story-based Arena portion of the game. The second disc held the "EX Arena", a large-scale Arena set up that allowed a player to face off against multiple opponents in multiple Arenas and unlock even more secret parts and earn even more credits. A "Ranker Maker" even existed which allowed players to create their own Arena stable with up to 10 fully customized opponents of their own making. One notable aspect regarding the parts (particularly weapons) in the original Armored Core and its two PS1 expansions is that they are by far the most powerful in the series. For example, the original KARASAWA fired faster than most AST Rifles and Pulse Rifles in later games. The FINGER had 3000 ammo (500 in Master of Arena), and the Large Missile came in two styles, one that flew like a regular missile (discontinued after Master of Arena), and the traditional slow (though roughly twice as fast as later versions such as those in Last Raven) version. The slow version had ten missiles (four in Master of Arena) as opposed to the current four, and was the longest range missile of the first generation (except in Master of Arena).