Nintendo's mascot Mario has appeared in literally hundreds of video games, from featured appearances to small cameos. But simply considering every game with "Mario" in the title equally and flatly as a "Mario game" isn't a very useful categorization. Surely there's some way to draw a line between the games like Super Mario Bros. and games like Dance Dance Revolution: Mario Mix.

But where is that line? How do we define what is a "core" Mario game and what isn't?

You probably think the answer is obvious and are developing your own list of "core" Mario games in your head right now. But I can assure you, your "obvious" answer is probably different from the "obvious" answer given by any other gamer you'd care to ask in some significant ways.

After days spent debating this definition with other gamers online and analyzing the results of a poll on the subject, I found Mario games can be divided into distinct tiers radiating outward from a central "core." I also found the debate over this simple definition has some interesting implications for how we view ever-evolving franchises and how we think about what games are important inclusions in the medium's still-developing canon.

The never-ending debate

My recent interest in the "core" Mario game question started innocently when the Pittsburgh Post Gazette's Max Parker asked me on Twitter what I thought of his contention that Super Mario 3D Land and 3D World are not part of the "core Mario series." The resulting epic Twitter argument drew in several other participants from the game journalism world and split off into numerous heated subthreads, eventually touching on the nature of scientific versus religious classification itself.

Much of the debate centered on whether there was a precise definition of a "core" Mario game or whether it's just something you feel in your gut on a case-by-case basis. And if there is a definition, what criteria go into it?

Some argued that just focusing on controlling Mario running and jumping was enough (but what about edge cases like Yoshi's Island or Super Mario Run?). Others felt some level of significant gameplay innovation was necessary or that the game's lasting impact on the genre should be considered. Can a game on a portable system be considered a "core" Mario game? Does the way Nintendo marketed the game matter (and how does Nintendo's own list of core Mario games factor in)? Does it matter if the game is, um, good?

Let’s settle this

Arguing over definitional issues like this with friends is one thing, but I wanted to get a broader idea of how gamers in general think about this question. So the next day, inspired by efforts like Fivethirtyeight's poll-based attempt to define the US Midwest, I set up a Google poll asking people to pick which titles fell into their definition of "core Mario game."

I asked respondents to "use whatever definition of 'core Mario game' you personally use" and offered up a multiple choice list of 61 potential choices (Mario has been in a lot of games). I did condense some series together for simplicity (if one Mario Kart game is core, probably all of them are), and I left out some straight remakes and obviously secondary titles (Mario Paint et al). Still, I tried to sample a wide range of games featuring Mario to get a precise idea of where people draw the line, personally.

In comments on the poll and on Twitter, some people came up with elegant definitions to slice the Mario pie. One suggested that only games with "Super Mario" (rather than just "Mario") in their title are part of the "core" (with the possible exception of the original Super Mario Kart). Another said that "core" Mario games are ones in which Mario runs toward a set end point and can collect and keep items permanently until getting hit (a strict definition that excludes games like Super Mario 64 and Galaxy).

Still others went more detailed: "If there's jumping, platforming, coin collection, stomping on enemies, bashing and breaking blocks (not just with hammers!), entering pipes, secret areas, mushrooms, stars and flowers as bonus items or abilities, bonus stages and/or minigames, multiple goals that aren't just to reach the end of the level, and performed by Mario or any of the main characters in the Mario universe—then it's a 'core' Mario game."

The most honest responses, though, realized there might be no strict way to settle the debate, even personally. "I can’t even do this. I can't decide in Mario what's core or not. I feel like all, but also some shouldn't be. I dunno," one respondent mused thoughtfully. "I can't rationalize my choices," another wrote in the poll.

Others found that just answering the question revealed deep personal truths about themselves. "Also realizing that I may actually count Super Mario Run as a 'core' Mario game makes me uncomfortable," Dan Carmichael wrote on Twitter.