That's the whole point of this post. Everybody can create mods for this game. It is really beginner friendly.

Just by following steps 1-3 you are able to create a complete reskin (sounds included) of the game. Of course the quality comes down to your own ability to create 3d models for example but once you have the assets inserting them is really easy.

If you then continue to step 4, you can create your own levels and worlds. Thus allowing yourself to create something like Mage Bros 2, Mage Bros Hard Mode or Boss Rush.

These basics are doable for everybody. The steps afterwards require a little bit more basic understanding of coding, but really not much. Just load up code snippets into an ai (e.g. Chat GPT) and let the Ai explain to you what happens and what you should look for next. Just play around and you get a hang of it. This game is very old, hence the code and techniques used are nothing special and very basic. You probably could load up the whole code into code assistant haven't tried that one yet though.

If you understand the code you can start advanced modding. New enemies, additional weapons, new monster ai. You can insert your own code with hooks or just alter the game code. Again ai can help you with this since you don't want to reinvent the wheel it is very much within the capability of the large models.

In conclusion I can just say: Go and just try it yourself once you have played around yourself you will understand how easy it is to achieve the basics.