The story is set several years after that of Contra III: The Alien Wars. It takes place in Damned City, where people go mad from being there. It takes a top-down isometric view. The game provides a single-player story campaign, multiplayer online cooperative, or four-player local cooperative (with separate Switch consoles) modes. It is based on player versus environment gameplay, with dual analog controller sticks.
Players assume the roles of four classic Contra series characters, as a former military group of bounty hunters and treasure finders: Kaiser, a rebuilt cyborg from The Alien Wars; Ms. Harakiri, an assassin with a parasitic alien attached; The Gentleman, a well-cultured alien bug; and Hungry Beast, a brilliantly scientific cyborg giant panda.
Players configure a main weapon and sub-weapon in realtime. These have unlimited ammunition, but with a heat meter to be managed. Between stages, weapons are upgraded and uniquely customized. As a last resort, the player can clear the area with a huge bomb or use the character's special ability.