Kamen Rider: Climax Heroes is a 3D crossover fighting game featuring the heroes of 10 different Kamen Rider TV series, from Kuuga through to Decade. The story is set in the Decade universe, where the worlds of the other nine Riders are all combining into one, and they must work together to save their worlds before they are completely destroyed. The game plays much like other 3D fighters such as Tekken, with the major addition being the so-called "Form Change" system that allows each Rider to transform during battle, and even in the middle of a combo. The main story mode is "Decade Mode", where the player must complete various missions with different characters to proceed through the story. There are also standard Versus, Survival, and Training modes. The game also includes a simple control option for younger players.

In Decade Mode, the player follows Tsukasa Kadoya's journey through the nine Heisei Kamen Rider worlds as Kamen Rider Decade, fighting the other Riders and attempting to prevent the destruction of the worlds. Decade Mode differs from standard gameplay in that Decade's Form Change and Special Attacks are customizable with KamenRide Cards and Final FormRide Cards earned as the player progresses. The missions in the mode are divided by three levels, with the easiest missions can be played in Level 1 while the hardest can be found in Level 3. Level 2 and 3 can be unlocked as the player progress in Level 1.