//Grab the target process by its name
Process targetProcess = Process.GetProcessesByName("Game")[0];
MonoProcess monoProcess;

//Try to attach to targetProcess Mono module
if (MonoProcess.Attach(targetProcess, out monoProcess))
{
    byte[] assemblyBytes = File.ReadAllBytes("TestInjection.dll");

    IntPtr monoDomain = monoProcess.GetRootDomain();
    monoProcess.ThreadAttach(monoDomain);
    monoProcess.SecuritySetMode(0);
    
    //Disable AssemblyLoad callbacks before injection
    monoProcess.DisableAssemblyLoadCallback();

    IntPtr rawAssemblyImage = monoProcess.ImageOpenFromDataFull(assemblyBytes);
    IntPtr assemblyPointer = monoProcess.AssemblyLoadFromFull(rawAssemblyImage);
    IntPtr assemblyImage = monoProcess.AssemblyGetImage(assemblyPointer);
    IntPtr classPointer = monoProcess.ClassFromName(assemblyImage, "TestInjection", "Loader");
    IntPtr methodPointer = monoProcess.ClassGetMethodFromName(classPointer, "Init");
        
    //Finally invoke the TestInjection.Loader.Init method
    monoProcess.RuntimeInvoke(methodPointer);

    //Restore the AssemblyLoad callbacks to avoid weird behaviours
    monoProcess.EnableAssemblyLoadCallback();    
    
    //You MUST dispose the MonoProcess instance when finished
    monoProcess.Dispose();
}