I plan on making my own games in the future, which will be either rpg or action/adventure with rpg elements. My early ideas have a detailed 2D design, which is how I want it to start out before the games evolve into 3D. The games have the same title, but some are unrelated to each other, taking place in a different universe.

Any suggestions on which system it should be on? I want some to be on a console and some on a hand-held.

For example, games like Homeworld: Cataclysm and Half-Life: Opposing Force are considered to be stand-alone expansions when they not only add new content, but completely replace content from the original games, whereas games like Doom II and Descent II do the same thing, but are always considered true sequels rather than expansions.