Sengoku is a 2D side-scrolling beat 'em up that casts you and a friend as two renegade fighters out to beat the crap out of the many assorted gangs that threaten the post-apocalyptic cities of the future. Unfortunately for them, they also get caught in a time-warping scheme caused by the evil Nobunaga who attempts to invade the time period with mythical warriors and evil creatures from the Japanese sengoku period.
The game takes you on a journey from the city to a spirit-realm from time to time, where you must fight all sorts of Japanese mythical figures. Your goal is to release three haunted spirits that can aid you in your battle. Defeated enemies leave behind colored orbs, which you can collect to heal up, gain weapons, and even get energy attacks. Green balls will increase your life gauge, while red balls give you a samurai sword, blue balls double your sword, and purple balls grant you a larger holy sword.
Defeating certain enemies will prompt a "I will help you" message, allowing the player to collect their soul. Pressing C at any time will summon the warriors' spirit, temporarily changing your character's form and giving you new attacks and powers. You can change form and fight as an armour-clad wolf, a samurai, or an agile ninja who moves around with back flips.