var count = 0;

onEvent("upButton", "click", function() {
  count = count + 1;
  setText("countDisplayLabel", count);
  if (count == 20) {
    setScreen("gameOverScreen");
    setText("finalScoreLabel", count);
  }
});

onEvent("downButton", "click", function() {
  count = count - 1;
  setText("countDisplayLabel", count);
  if (count == -5) {
    setScreen("gameOverScreen");
    setText("finalScoreLabel", count);
  }
});