I am trying to make Arduino Uno to act as a keyboard. I have successfully flashed the USB-HID firmware in it using this link also and programmed it like this.

uint8_t buf[8] = {
 0
};

int inpin1 = 7; 
int inpin2 = 8;
int val1 = 0;
int val2 = 0;

void setup() {
  Serial.begin(9600);
  delay(200);
  pinMode(inpin1, INPUT);
  pinMode(inpin2, INPUT);
}

void loop() {
  val1 = digitalRead(inpin1);
  if(val1 != HIGH) {
   buf[2] = 80; // Left Arrow
   Serial.write(buf, 8);
   releaseKey();
  }
  val2 = digitalRead(inpin2);
  if(val2 != HIGH) {
    buf[2] = 79; // Right Arrow
    Serial.write(buf, 8);
    releaseKey();
  }
}

void releaseKey() {
  buf[0] = 0;
  buf[2] = 0;
  Serial.write(buf, 8);
}

The above code works fine but the problem is that when I tried to play a game, which uses right arrow and left arrow, and to control a car I was using the push button, which I connected to Arduino as left and right arrow keys. But suppose I want to turn a car. I have to press the key and then release the key to move it a very little to the right or left. So, if I want to turn the car either left or right, I have to press and release so many times that it becomes impossible to play the game. Do you anyone know how to resolve this problem?