Let me structure the article accordingly: introduction, official releases on PC (which are limited), legal access methods, fan projects, cultural impact, and conclusion. Make sure to emphasize legal and authorized ways. Maybe include examples like Switch Online + Expansion Pack 2 which includes some 2D games.
I need to make sure the information is accurate and stays within legal boundaries. Mention that using emulators without owning the original games isn't legal, so it's important to highlight legal alternatives. Also, mention fan games as non-commercial, created by enthusiasts.
Alright, that's a plan. Now, structure the article with these points, ensuring accuracy and legality. Avoid mentioning piracy explicitly, focus on legal options and fan projects.
Double-check the current available games on PC. Mario Kart Tour was a mobile game, but nothing from the main Mario series on PC. The user might have heard about a hypothetical "Super Mario 2D Universe" collection, which doesn't exist. So the article should clarify that while there's no official PC-exclusive 2D Mario collection, there are ways to access existing 2D games through legal means.
Also, the user might be interested in mods or fan-made games. There are projects like Super Mario World hacks or fan games like SMBX. Maybe include those as creative extensions of the 2D Mario universe.