Прошу найти недостатки моего кода

       
            // Initialization class Random
 
            Random Random = new Random();
 
            // Start menu (Choose numbers of examples)
 
            Console.WriteLine("Welcome to the MathMaster game!");
            bool CheckFormat;
            int NumberExamples;
            do
            {
                Console.Write("Enter the number of examples: ");
                string text = Console.ReadLine();
                CheckFormat = int.TryParse(text, out NumberExamples);
                if (!CheckFormat)
                    Console.WriteLine("You must enter a number!");
            } while (!CheckFormat); // Ask number of examples, with foolproof
            int difficulty = 0; // Uneven complexity
            do
            {
                CheckFormat = true;
                Console.Write("Select difficulty (Easy, Normal, Hard): ");
                string text = Console.ReadLine();
                if (text == "Easy")
                    difficulty = 10;
                else if (text == "Normal")
                    difficulty = 100;
                else if (text == "Hard")
                    difficulty = 1000;
                else
                {
                    CheckFormat = false;
                    Console.WriteLine("Wrong difficulty");
                }
            } while (!CheckFormat); // Select difficulty, with foolproof. This part is planned to be transferred to something smarter, but so far I do not know what, maybe tuples or list
            Console.Write("Ready? Tap any buttons to start");
            Console.ReadKey();
            Console.WriteLine();
            Console.WriteLine();
 
            // Body
 
            Single AllTime = 0; // Sum the solution time of all examples.
            int Counter = 1;
            int score = 0; // Score = 100/(Current sample time). If time ~ 0 => score = 100, if time ~ infinity => score = 0
            int CorrectAnswers = 0;
            string Mistakes = null;
            Stopwatch TimerAnswer = new Stopwatch(); // Initialization method for timer
            char[] ArraySymbol = { '+', '-', '*', '/' }; // Solution that eliminates the "switch" and "if". (part 1)
            do
            {
                // Initialization variable
 
                byte FirstNumber = Convert.ToByte(Random.Next(1, difficulty));
                byte SecondNumber = Convert.ToByte(Random.Next(1, difficulty));
                if (SecondNumber > FirstNumber)
                {
                    byte Tempo = FirstNumber;
                    FirstNumber = SecondNumber;
                    SecondNumber = Tempo;
                } // For convenience of solve, if the second number is greater than the first, they will change.
                byte Symbol = Convert.ToByte(Random.Next(0, 4)); // Random symbol (+-*/)
                Single[] ArrayCorrectNumber = { FirstNumber + SecondNumber, FirstNumber - SecondNumber, FirstNumber * SecondNumber, FirstNumber / SecondNumber };
                // A stupid solution that eliminates the "switch" and "if", but forces you to do extra calculations. (part 2)
 
                int answer;
 
                do
                {
                    TimerAnswer.Reset(); // Reset Timer
                    Console.Write($"[Score: {score}] {Counter}. Calculate: {FirstNumber} {ArraySymbol[Symbol]} {SecondNumber} = ");
                    TimerAnswer.Start();
                    string text = Console.ReadLine(); // Made to make the timer as accurate as possible.
                    TimerAnswer.Stop();
                    CheckFormat = int.TryParse(text, out answer);
                    if (!CheckFormat)
                        Console.WriteLine("Wrong format answer!");
                } while (!CheckFormat); // Input answer with foolproof
                TimeSpan TimeAnswer = TimerAnswer.Elapsed; // Read the values
                if (answer == ArrayCorrectNumber[Symbol])
                {
                    CorrectAnswers++;
                    Console.WriteLine($"Right! {TimeAnswer.Seconds},{TimeAnswer.Milliseconds} sec");
                    score += Convert.ToInt32(100 / (Convert.ToSingle(TimeAnswer.Seconds) + (Convert.ToSingle(TimeAnswer.Milliseconds) / 1000)));
                } // Checks the correctness of the answer
                else
                {
                    Console.WriteLine($"Wrong! {TimeAnswer.Seconds},{TimeAnswer.Milliseconds} sec. Correct answer: {ArrayCorrectNumber[Symbol]}.");
                    Mistakes = Mistakes + $"{Counter}. Calculate: {FirstNumber} {ArraySymbol[Symbol]} {SecondNumber} = {answer}. Correct answer: {ArrayCorrectNumber[Symbol]}. \r\n"; // Counts mistakes and makes one big string of delimited mistakes. 
                }
                AllTime += Convert.ToSingle(TimeAnswer.Seconds) + (Convert.ToSingle(TimeAnswer.Milliseconds) / 1000);
                Counter++;
            } while (Counter <= NumberExamples);
 
            // Output information
 
            Console.WriteLine($"You scrore - {score}, number of correct answers - {CorrectAnswers}/{Counter - 1}, Time - {AllTime} sec.");
            Console.WriteLine();
            Console.WriteLine("You mistakes: ");
            Console.WriteLine();
            if (Mistakes == null)
                Console.WriteLine("None");
            else
                Console.WriteLine(Mistakes);
            Console.ReadKey();
 
            // To do list:
            // 1. Record clocks and time limiters, because if the time is more than 60 seconds, it will go in a circle, and so will I   :3
            // 2. Smarter difficulty
            // 3. More settings and features
            // 4. Help for users
            // 5. Optimization
            // Comments:
            // Random.Next(>=, <)
            // 0 < byte < 255