counter doesn't work

Mantas Gudauskas The parseInt(prompt(question)) method in the for loop is intended to convert the string answer from the prompt into a number. In the video, all the answers are numbers, so the method is appropriate. All your answers, however, are strings, and aside from question two, none of these can be converted into numbers.

So you will need to slightly simplify your code and change the value of the response variable to the string the user types in the prompt. If you go to the response variable in your for loop and remove parseInt( method and the second closing parentheses after question, your code will work. Your loop should look like this:

for (var i = 0; i < questions.length; i += 1) {
  question = questions[i][0];
  answer = questions[i][1];
  response = prompt(question);
  if ( response.toLowerCase() === answer ) {
    score += 1;
  } 
}

If you wanted to use both numbers and strings for answers and use the parseInt method, you could add an OR operator and change your if statement to:

if ( response.toLowerCase() === answer || parseInt(response) === answer )