My tutorial series started out with a block platformer
because it's generally the easiest type of action game to make. Master the block platformer and you can move on to bigger and better things... the block platformer model will get you accustomed to sprite movement technique and collision, plus enemy movement theory if you so desire. You can then take that experience into more complex game types, such as "pure" platformers (moving platforms and slopes), shooters (prepare to optimize the snot outta your code, and basic AI helps unless you wanna just do movement tables), or perhaps brawlers (Y-sorting, complex hitboxes, strong AI). Fighting games come off as simple at first, but are AI-heavy and you need a
strong understanding of finite state machines to pull them off. They're way more advanced than they look. And RPGs... forget it... you pretty much have to be an expert at
all of this before you attempt an RPG. Sure, you can scrape by with basic understanding of solid-block collision, and when planned carefully, you can avoid getting into Y-sorting... plus you can skip AI altogether if you want your enemies to be a band of blundering dumbasses who, one would wonder, ever got around to doing whatever foul deeds your story says they did. To make a masterpiece though, you'll need all the skills for that, plus some that are unique to RPGs, such as the ability to handle vast amounts of text (you'll have to use far storage, which requires some advanced techniques). You might even want to utilize subtile collision, which means you'll have to understand and effectively use subtile collision maps... which also means you'll need to understand granularity and lookup tables (this is helpful for pure platformers, though most times, you can just get away with a slope table as opposed to a subtile collision map). RPGs are a
nightmare to do properly on the PCE.
A platformer is an awesome first project and is one of the most satisfying types of games to both make and play.