Sengoku is a 2D side-scrolling beat 'em up where you play as two renegade fighters battling against various gangs in post-apocalyptic cities. However, they soon find themselves caught in a time-warping scheme by the evil Nobunaga, who attempts to invade the future with mythical warriors and creatures from Japan's sengoku period.
The game takes you through both city levels and spirit-realm levels, where you must fight Japanese mythical figures and release three haunted spirits to aid you in battle. Defeated enemies leave behind colored orbs that can be collected for healing, gaining weapons, or energy attacks. Green balls increase your life gauge, while red, blue, and purple balls give access to specific swords.
Throughout the game, certain enemies will prompt a "I will help you" message, allowing you to collect their souls. Pressing C at any time summons the warriors' spirit, temporarily changing your character's form and granting new attacks and powers. You can fight as an armour-clad wolf, samurai, or agile ninja, each with unique movements and abilities.