Stay Cool, Kobayashi-San!: A River Ciy Ransom Story

Stay Cool: Kobayashi-San!: A River City Ransom Story is a beat 'em up game in the Kunio-Kun series. It was released by Arc System Works for the Nintendo Switch in November 2019.

Gameplay
Up to two players can play the game together. In the single player mode, the second character is controlled by the CPU. The game has no friendly-fire option or difficulty selection.

When first starting the game, players first create Kobayashi's friend. The character has to be named, assigned a gender, and the kind of relationship they have with Kobayashi (Friendship or Love). Following that, the player selects three items that symbolize the memories of Kobayashi with this friend. Players are then taken to the game's prologue. Once the prologue ends, players are placed in a random area to start the game.

The game's objective is to defeat the leaders of the evil organization and rescue Kobayashi's friend. To accomplish this, players must defeat 30 fighters linked to each leader. Once the player defeats 30 fighters of the same color, their leader spawns. Once all leaders are defeated, the mastermind will be revealed. Once defeated, Kobayashi's friend is rescued and the player gets to see the ending.

Completing the game will probably not unravel whatever scheme the evil organization is planning, the player will need to replay the game multiple times to uncover the truth. While the player is on their adventure trying to find Kobayashi's friend, they will run into different characters with their own secrets and motivations, as well as new enemies. Meeting certain conditions during the game will reward player's with the true ending.

Mizoguchi and Kunio are with Kobayashi from the start of the game. Kobayashi must be on the screen at all times, the player can freely switch between Mizoguchi and Kunio. Players can also choose to control Mizoguchi or Kunio instead of Kobayashi. Both of these actions can be performed with a button press or in the pause menu. In single player mode, if Kobayashi loses all of his health, he will be exhausted and Mizoguchi will be forced to rewind time, regardless of how much health Kunio and Mizoguchi have.

Mizoguchi is equipped with three items, one is used for Recovery, the other is to call in Helpers, and the last one is to Power Up Kobayashi. These items can only be used by Mizoguchi, so he must be on the screen to use them (Kunio can be tagged in while or after this items are used, however). When first starting the game, the Helper item will summon Ryūichi. After defeating two leaders and meeting Tōdō again, he will allow Ryūji to tag along with Kobayashi. When the Dragon Twins are summoned, they join Kobayashi and his friend for a limited amount of time, but the player can control them in the same way as Kunio and Mizoguchi.

Defeating a leader and completing the game rewards the player with stars. These stars are used to power up the characters with skills and to purchase new items for Mizoguchi.

Plot
At Reihō Academy were the "Shitennō of Reihō" feared by nearby schools. The man that reigns at the top of that group is Masao Kobayashi. But there was another side to him...

After a "certain incident" when he was in middle school, Kobayashi met a young man named Kouki Mizoguchi. Mizoguchi is a man of mystery chasing down an "evil organization".

Mizoguchi, who noticed a glimpse of a "certain power" within Kobayashi, works alongside him to destroy this evil organization.

One day, Kobayashi's friend is kidnapped by the evil organization. Kobayashi plays it cool, but inside he was enraged...

To save his friend and destroy the organization, Kobayashi will fight against them.