Ka 2 is the Japanese-exclusive sequel to Mister Mosquito. Once again, the player assumes the role of a mosquito that must drain human blood to survive. This time, there's a choice between American and Japanese mosquitoes, each attacking a family of its nationality.
The player controls the mosquito, flying around the room where the victim takes a rest. When approaching the human, the possible target areas on the body glow green. When the insect lands on those places, a small zoom screen shows the exposed skin and the mosquito ready to attack. Pressing the analog button makes the bug bite the victim, and moving the analog control fast starts the pumping action, where a syringe starts to slowly fill with blood. The danger of the human swatting the bug increases as the skin surrounding the bite gets more red.
Sometimes the human gets up and starts to search for the mosquito. Green beams shine forth from the eyes, and the player must maneuver the insect out of its reach. When engaging in battle mode, the mosquito must bite certain body parts to decrease the human stress shown at the bottom of the screen.