a snippet to override the game over method of the offline built-in t-rex game.

GoogleChromeDinoGameOverOverride.js

/*

  source code: https://source.chromium.org/chromium/chromium/src/+/master:components/neterror/resources/offline.js

  paste into address bar: chrome://dino/

  then before starting game, press F12 to open the Chrome developer console
  and then paste this code snippet to override the game's gameOver() method.

  enjoy!

  ~Bu

*/
Runner.instance_.gameOver = () => {
  context = Runner.instance_;

  // do not stop the game, just penalize the player.
  const penalize = () => {
    // hitting obstacle should slow down dinosaur.
    const baseSpeed = context.config.SPEED / 2;
    if (context.currentSpeed > baseSpeed) {
      context.currentSpeed -= baseSpeed;
      context.currentSpeed *= ((100 - 5) / 100); // 5% reduction.
      context.currentSpeed += baseSpeed;
    }

    // penalty is set at 10 distance run per 100 whole distance run laps.
    const cost = 10;
    const lap = 100;
    penalty = Math.floor(context.distanceRan / lap) * cost;
    context.distanceRan -= penalty;
  };

  // hit immunity for a certain period of time.
  const currentTime = (new Date).getTime();
  if ((context.immunityTimeout ?? 0) < currentTime) {
    context.playSound(context.soundFx.HIT);
    vibrate(200);
    penalize();  // penalize first, then let the immunity take effect.
    const immunityTimeout = currentTime + (1 * 1000); // 1 second immunity
    context.immunityTimeout =  immunityTimeout;

    // TODO: set a timer instead to periodically save the highscore.
    if (context.distanceRan > context.highestScore) {
      context.saveHighScore(context.distanceRan);
    };
  }
};