Hey, glad you like it that much! There are some great tutorial shaders on shadertoy and if you're looking to achieve a specific thing you should definitely look there. Are you looking for tutorials on how to program shaders, or how to achieve certain styles?
Ok, I don't really know of any tutorial on specifically that. I do have a tutorial that I made for this project, you can find that here. Best advice I can give you is to first become familiar with shaders, then it will be easier to achieve certain looks.
For the pixel style I usually just browse some pixel art until I find something I like, then I loosely base my stuff on that.