installer/Aki.Helper/GameHelper.cs

using Microsoft.Win32;
using System.Runtime.InteropServices;
using System.IO;

namespace Installer.Aki.Helper
{
    public static class GameHelper
    {
        private const string registryInstall = @"Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\EscapeFromTarkov";

        public static string DetectOriginalGamePath()
        {
            // We can't detect the installed path on non-Windows
            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
                return null;

            var uninstallStringValue = Registry.LocalMachine.OpenSubKey(registryInstall, false)
                ?.GetValue("UninstallString");
            var info = (uninstallStringValue is string key) ? new FileInfo(key) : null;
            return info?.DirectoryName;
        }
    }
}