The gameplay of Warriors All-Stars is modeled after the hack-and-slash Warriors series, in which the player controls a single character to defeat enemies throughout a stage while trying to achieve a specific goal. In Warriors All-Stars, each player may also select four supporting characters to assist the chosen character; the supporting characters lend additional abilities that may be triggered by holding down R1 and selecting a face button. Certain pairs of characters, when assisting the character at the same time, may combine their attacks for additional effect.
Although the game uses the Warriors Orochi series as its inspiration, the game engine is highly reminiscent of Samurai Warriors: Spirit of Sanada and gameplay is closer to that of Dynasty Warriors 8: Empires. All characters have a similar movepool of a normal attack chain of six attacks, and six charge attacks, as with the Dynasty Warriors series. In addition, effort was made so that each character’s moveset remains true to their series of origin (Ryu Hayabusa, Ayane, and Kasumi, who previously appeared in Warriors Orochi 3, have their movesets entirely redone as a result). Samurai Warriors series characters have their normal and hyper attack chain shortened to accommodate the attack system, though they are given a sixth charge attack to compensate; Dynasty Warriors series characters have some of their charge attacks altered either visually or in their function for this game.
As not every character is armed with a weapon, as is traditional in Warriors games, character growth instead focuses on hero cards, which take the place of weapons in this game. Hero cards may be equipped to a corresponding hero, and grant the hero increased abilities. Each character may have up to 20 cards in their inventory, although only one may be equipped to a character at any given time. Unwanted and excess hero cards may be sold for gold between missions or disassembled for materials that may be spent to enhance other hero cards. Gold may also be spent to level up characters, though only to the highest-levelled character currently available to the player.
The stages featured are themed after the series of origin for the various characters, though some stages are taken from Samurai Warriors 4 and Dynasty Warriors 8 series games, either taken as-is or themed to another series’ visuals. (This had also occurred with Warriors Orochi 3 series games as well.) Visuals include a Nara-era Japanese garden and a medieval European ruins were featured, based on Toukiden: The Age of Demons and Atelier titles, respectively. Music for the game primarily consists of remixed versions of theme music from the characters’ series of origin. Most themes contain two mixes: a “Starlet Mix” that is primarily orchestral in nature, and a “Stars Mix” that is similar, but places greater prominence on rock instruments, as traditional in the Warriors series.
The game story features a scenario that unfolds based on the initial character chosen at the start of the game. The storyline is nonlinear, and may be advanced at a player’s own pace. Most missions do not advance the plot, and merely serves as side missions meant to raise a character’s skills and abilities, akin to Free Mode in other Warriors games. “Hero Battles” allow additional characters to be unlocked, while “Key Battles” advance the story. The completion of certain Key Battles may prevent the player from participating in other missions, and some Key Battles may require that characters be unlocked through Hero Battles before they may be played. There are 15 total endings in Warriors All-Stars, necessitating multiple play-throughs in order to experience the complete story.
The game is strictly single-player, though the producers have not ruled out a future update that includes multiplayer functionality.