After a mysterious force from space hit the earth, scientists who try to discover what the force was had lost their minds and began to fight with each other to obtain it, but when fighters gathered around it, they had not gone mad but had felt stronger than before; it was named "Kämpfer". Knowing about this alien force, Heihachi Mishima had opened another Iron Fist Tag tournament, this time calling it: "Tenka Tekken," and used the Kämpfer to set the stages for the fighters of this new Tekken Tag Tournament.
Players are able to switch their fighters out at any time, allowing the inactive character to gradually recover some life they might have lost. At certain points, an inactive character's life bar may flash, giving them a temporary boost in strength if they are tagged in. If the life bar of either of a player's fighters runs out, that player loses the round. If time runs out, the player who has the most cumulative life remaining amongst their fighters wins the round.
The gameplay uses the same fighting mechanics as Tekken Tag Tournament 2, being able to use Tag Assaults and "Bound" hit. Like the Strongest Under Heaven series, certain parts of a characters clothes could be ripped off or removed when a part of the body is injured enough.
Players can use each button to string together combination attacks, as well as perform special moves using a combination of button presses and joystick movement. As characters attack, their Special Gauge fills with energy which can be expended by the player to execute powerful Special Combos and Team Combos that involve multiple characters. The game also includes Mission Mode, which features character-specific challenges geared towards helping players explore the control scheme and preparing them to play against other people, and Shadow Mode, a series of downloadable packs which allows the player to fight against a team of AI opponents programmed after the techniques and preferences of Namco's development staff and other players who upload their gameplay in Shadow Mode to the Tenka Tekken console website.
Players will use their team of two characters to defeat a series of AI-controlled opponents before battling the game's final boss, Kämpfer Heihachi; each character has their own unique ending sequence, which they earn upon completion of Arcade Mode. Tenka Tekken includes an online play mode using Microsoft's Xbox Live and Sony's PlayStation Network services. When an online match begins, both players can view their opponent's License Card. License Cards keep track of player tendencies based on fighting style, record player points and total number of wins and losses, and allow players to see the positive and negative points of their play styles.
The game features a total amount of 60 playable characters from both the Tekken and Strongest Under Heaven series' including three original characters and one guest character.