The while-validation had to continue until energy drops below 0. Also you had to break from the loop as soon as the distance became bigger than the remaining energy.

Best,

using System;

namespace Counter_Strike
{
    class Program
    {
        static void Main(string[] args)
        {
            int initial = int.Parse(Console.ReadLine());
            int distance = 0;
            int wins = 0;
            string command = string.Empty;
            while (initial >= 0)
            {
                command = Console.ReadLine();
                if (command == "End of battle")
                {
                    break;
                }
                else
                {
                    distance = int.Parse(command);
                    if (distance > initial)
                    {
                        Console.WriteLine($"Not enough energy! Game ends with {wins} won battles and {initial} energy");
                    }
                    initial -= distance;
                    wins++;
                    if (wins % 3 == 0)
                    {
                        initial += wins;
                    }

                }
            }
            if (initial >= 0)
            {
                Console.WriteLine($"Won battles: {wins}. Energy left: {initial}");
            }
        }
    }
}