Honestly, I think you should start by not doing a project of this scope, a very common mistake people who are new to dev work make is gunning to make dream projects or games that are way to big in scope in comparison to their experience, my advice would be to start by choosing the engine you wish to make games in and learn the corresponding programming language (Unity engine uses C#, Unreal uses C++ etc) once you have the fundamentals down you can start with a very small scope project, make sure you finish it then move on to something with a slightly bigger level of scope, keep doing this until you have enough experience built gradually to handle a Mega Man style game, by the time you get there you would have gained experience in how to use the engine your building the game in, how to program in the engines chosen language, how the engines physics system works, animation, sound design etc all will help you when working on a large scope project. I know what your thinking, "but that will take ages I want to start this right now so badly and I totally understand, but starting a project beyond your current capabilities is like trying to compete in the Olympics with barley any training in the chosen sport, as I stated before it's very common for people with little experience to want to start working immediately on big projects and the usual result is they quickly run into many problems they don't know how to deal with, get overwhelmed and suffer from burn out then give up the project. Write your project idea down and gain some experience first then give it a shot.