Destiny, a post-apocalyptic video game that comes out on Tuesday for PlayStation 4, PlayStation 3, Xbox One and Xbox 360, is the most pre-ordered video game in history. That's according to both retailer Gamestop and publisher Activision, setting up massive expectations for the title even before it's officially on sale.

Although you might have seen the Destiny billboards or other bits of the game's extensive marketing campaign, those who haven't been waiting for its release for years might not really get what the excitement and hype are all about.

This guide probably contains nothing new to those who have already pre-ordered the game, so feel free to keep counting down the hours until midnight. For everyone else, here's a basic rundown of Destiny, and why it's important.

Let's start with the gameplay trailer, which racked up more than 6 million views in just a few weeks:

What's the excitement?

If the trailer above didn't grab you, it might help to understand that this title comes from the makers of one of the most popular games ever. And it's been in the works for a long time. Destiny's developers, Bungie, also developed Halo. Even many non-gamers know about Halo. Please tell me you know about Halo, at least as a cultural reference point. The series is huge. Bungie teased its new project in 2009 during the release of Halo 3, but fans didn't really hear much more after that until a couple of years ago.

With that in mind, one could think of Destiny as what happens when Halo's creators really, really apply themselves. In other words, gamers (well, many of them) are expecting something spectacular and new and different from Destiny, and they're willing to bet the purchase price on it.

The game's publisher, Activision, certainly hopes that Destiny will reach Halo's cultural heights and beyond, as Gamespot noted. Wired did a big piece on Destiny that goes into this hope in depth.

Building on that excitement: the success of the game's beta, or test, release earlier this summer. More than 4.6 million people downloaded the beta. That's a large city of people, all interested in a months-long test game that they'd then have to buy later. As Polygon notes, Destiny's beta size is about double the amount of players who downloaded the beta version of the hugely-successful Titanfall game, which came out last spring. At the time, Titanfall's beta size made it a "major collective event" in gaming.

Also, one of the game's developers is literally jumping out of a plane to help promote it, so there's that, too.

What's it about? 

Destiny takes place in a post-apocalyptic solar system some time in the future, after a mysterious, cataclysmic event that has devastated most of Earth and wiped out the human race's colonies on other planets. The survivors are concentrated in one Earth city, protected by a mysterious orb called the "Traveler." But the Traveler's protection is limited. Enter the Guardians, humans who guard the city and fight against the hostile aliens now occupying much of humanity's former empire.

Players take on the role of a Guardian and get to choose one of three "classes" to play. Each class comes with different strengths and weaknesses. There are Hunters (space bounty hunters), Warlocks (space wizards) and Titans (space marines). As a Guardian, you explore the expansive world and do what's needed to preserve humanity.

The developers have more plot details in the lengthy "reveal" trailer from 2013 here.

What kind of game is it?

Until actual players get into the world and start figuring it out, that's up to debate. Bungie once called it a "next-gen first person shooter," but it has elements of what are typically called Massively Multiplayer Online games, or MMOs. Those games let you interact with other players over a live server, in addition to the game elements itself. But Bungie insists that Destiny is more than either of those traditional categories. The engineering lead for the game called it a "shared-world shooter," Kotaku reported. As you walk around the world, players will find free-for-all areas and smaller group zones, where the game will "match" you with players instead of just showing you everybody at once all the time.

That boils down to a few things: Destiny players are expecting a lot of character customization, a very open world, a plot that doesn't really have a set ending, and a lot of cool new features. For that reason, the game's makers are encouraging players to withhold their final judgments until they actually spend some quality time with the world. They wrote: "Destiny isn't Destiny without the most crucial component to our living, social world: You."

Bungie seems to be hoping that its inability to clearly explain what, exactly, Destiny is like will translate into an addictive social experience that its early adopters will keep coming back to (ideally, with their friends).

Hey, I still don't care about this game. Are you a liar?

Maybe, I guess. But here's one more thing to keep in mind: This is a big, and growing industry, whether you care about it or not.

Whether it's sales or sexism, general interest publications sometimes lapse into discussing games and gamers as a teeny tiny niche market for a subset of nerds. In fact, it's actually a huge, growing industry that attracts a wide range of people. Depending on the survey, as many as 67 percent of households play games in some capacity -- which, Consumerist noted, places it in the mainstream for cultural consumption alongside TV watchers and moviegoers.

Still not convinced? In 2013, the gaming industry took in $21 billion in sales.

Although over-hyping is always a danger, Destiny could be positioned to become the next big thing in that industry. Even before Tuesday's official launch, its publishers already want the industry to think of it as the latest billion-dollar franchise.