Tomorrow evening, Sony is widely expected to unveil its fourth-generation PlayStation, which could become Sony's biggest product launch of the year. In fact, it could be Sony's biggest launch for the next half decade.

That's thanks largely to the PlayStation brand's proud lineage: the original PlayStation put arcade-quality gaming into homes around the world, the PlayStation 2 drove DVD adoption and amassed the most comprehensive video game library of all time, and the ambitious PlayStation 3 is arguably the main reason we still have Blu-ray today. So there's a lot at stake for Sony's all-but-certain PlayStation 4 — or whatever the name may be — when it's announced tomorrow evening. PlayStations are more than just game machines; they're supposed to be revolutionary pieces of hardware that push the boundaries of technical innovation in the living room.

Can Sony do it again?

This isn't 2006

More than ever, the console business — a stronghold for Sony for nearly two decades — is seeing intense pressure as technology and business models are changing. Physical media is dying for movies and games alike. Non-traditional market players like Apple and Google are just a heartbeat away from turning their widely deployed set-top boxes and televisions into serviceable casual gaming machines. And thanks to the advent of cloud gaming, it's not even clear that end users need their own hardware horsepower anymore.

That's all going to play a big role in what the PlayStation 4 — codenamed "Orbis" — ultimately becomes. But at the end of the day, it's still a game console. And the games need to be good.

The games

Here's where the situation gets murky: no one actually has any idea what a "next-generation" video game is supposed to look like. In the past, PC games provided a blueprint for upcoming consoles; by the time Sony, Nintendo, and others needed to release new hardware, the PC was so far ahead that it was easy to see what was in store. That's simply not the case this time around, however. PC games certainly look much better than those available on seven- and eight-year-old console hardware today, but market realities mean that graphically intense AAA titles now must be created with consoles in mind. While PC titles run at sharper resolutions and smoother frame rates — Polygon just called Crysis 3 the best-looking game ever created — they tend to be fundamentally the same game as what's offered on console. Compare to 2006, when the thought of playing something like The Elder Scrolls IV: Oblivion on a PlayStation 2 would have been laughable.

So, Sony has quite the challenge on its hand: the PlayStation 4 can't simply display graphics on the level of current PC games. Releases will have to look better than those games, otherwise customers will quite reasonably ask why the same title couldn't run on a PlayStation 3 without the need for an expensive new console.

What about launch titles? One name often mentioned is Watch Dogs, a title shown off by Ubisoft at last year's E3 and apparently set for "all home consoles" this holiday season. It looks impressive enough that we wouldn't be surprised to see it significantly pared down for current-gen systems, with a full version coming to the PS4 and its next-gen Xbox counterpart. The same goes for Metal Gear Solid: Ground Zeroes, which developer Kojima Productions insists was demoed on PC hardware equivalent to a PS3, but looks suspiciously high-fidelity to us. Destiny, the new game from Halo creators Bungie, is also rumored to make its way to next-generation platforms. An outside bet is The Last Guardian, from the developers of PS2 classics Ico and Shadow of the Colossus. In development for several years with little in the way of results to show for it, original director Fumito Ueda posted an update last week to say that more would be revealed soon. Could it have been shifted from PlayStation 3 to 4? The same thing happened to Ico, which started development as a PS One title, so we're ruling nothing out.

The controller: a gateway to social networking?

As with every console, the PS4's controller is an area of intense speculation — you hold it for hours on end, so it needs to be good. An alleged photo of a prototype PS4 pad leaked out last week; it looks to keep the same basic layout and shape that Sony has used since the original PlayStation, but with some fresh twists.

The center of the controller is dominated by a PS Vita-style touchpad, which could offer an additional form of analog input next to the traditional sticks. A blue light at the top looks like it may handle PlayStation Move-style pointing functionality, though we can't see the controller itself working too well as a tennis racket substitute in motion games — nor is Sony likely to push gyroscopic motion control as a major feature, given the failure of PS3 titles such as Lair that relied on the similar Sixaxis sensors. Other changes include what appears to be a headphone jack on the bottom, a speaker below the touchpad, and longer handles that are reminiscent of the first PlayStation's original analog controller before the addition of rumble. Kotaku reports that every PlayStation 4 will come with the PS Eye camera needed for Sony's brand of motion control.

The controller prototype has another unlabeled button of no obvious function, but it could well tie into the PlayStation 4's social media capabilities. According to Edge, the PS4 controller will feature a dedicated "Share" button that allows players to post screenshots and videos to various social networks, and the Wall Street Journal reported yesterday that Twitter, Facebook, and YouTube will factor prominently. If Edge's source is to be believed, the PS4 constantly records gameplay with no processing penalty, and at any point the last 15 minutes of footage can be edited and posted online. This sounds like a fantastic idea, if one we've heard before: the ill-fated OnLive streaming game service let you push a button to capture the last ten seconds of gameplay, and it led to a collection of hilarious videos of gaming accomplishments. It's a neat way for players to get involved with their games, and would guarantee a source of viral, word-of-mouth marketing with next to no effort on Sony's part.

The cloud takes a starring role

With Sony's acquisition of Gaikai last year, it's reasonable to assume that cloud gaming will form part of the PlayStation 4 strategy, and just today we got word of a possible service called PlayStation Cloud through some leaked domain registrations. According to the Wall Street Journal, Gaikai technology will be used to provide backwards compatibility with the PlayStation 3; players will be able to stream games online from Sony's servers. The Journal's report doesn't cite any other examples, but there are many possibilities for where Sony could take the service. Saving games to the cloud is a given, as it's already implemented on the PlayStation Plus service for PS3 and Vita, but a cloud gaming service could save the exact state of your game. Could Sony allow you the possibility to finish playing a game on the couch, and immediately pick up where you left off by using a Vita?

Similarly, The Journal's sources also say that Sony may support multiplayer gameplay across devices, for example between a smartphone and a console, and this could benefit greatly from cloud gaming. Right now, gamers can play against friends on console using a handheld device, but only when the games have been built explicitly with that in mind, and aren't too graphically intensive for a handheld to run. With Gaikai, this could become a standard feature: you could theoretically play the exact same game on any system, because neither would be running on the actual hardware in your living room.

But beyond the Gaikai rumors and vague rumblings about social sharing, the online capabilities of the PlayStation 4 are an unknown quantity. The PlayStation 3's connected features have been overhauled so dramatically over the console's lifespan that the system is barely recognizable today, so its successor will have a fairly solid baseline to work from. The usual array of streaming video apps and Sony's own media services are a given, as is gaming functionality via the PlayStation Network, but there's little indication of how the company might attempt to improve on the PS3 as a connected media box. Xbox Live still provides the more advanced online gaming experience in a few key areas, too, and Sony will likely look to close the gap.

It'll be interesting to see what the company does with PlayStation Plus in the next generation; the service has grown into an excellent value addition to the PlayStation platform, offering a steady stream of free and discounted games for about the same price as an Xbox Live Gold subscription. A lot of people are happy to pay for Xbox Live, though, so Sony may well be tempted to try and secure more subscribers this time around — either by boosting PlayStation Plus benefits or following Microsoft's lead by putting console features (like online multiplayer) behind a paywall. Sources already say that might be the case. It might make sense to restrict cloud services to paid customers, and the current incarnation of PlayStation Plus already has some features in this vein such as automatic software updates and online savegames.

PS Vita's second chance?

Speaking of the Vita, the next PlayStation could provide a shot in the arm to Sony's portable in a few ways. Besides the possibility of streaming full console games to the Vita over the cloud, there's a lot of scope for what it could do over a local connection in the living room, too. The obvious example is Wii U-style second screen functionality — there's no reason why Sony couldn't get the two systems to talk to each other in the same way, and some PS3 games such as LittleBigPlanet 2 have already experimented with using the Vita as a controller. It's unlikely many users would buy a $250 portable console expressly for that purpose, but with SmartGlass already a part of Microsoft's current-generation strategy, it seems a sure thing that Sony will announce some sort of second screen feature for the new PlayStation. If not the Vita, then perhaps your smartphone will be able to control the system, as Kotaku is reporting. (Incidentally, the Vita received a 20 percent price cut in Japan this week, and Sony could well announce a similar drop for the US at tomorrow's event.)

Another battle with Microsoft for next-gen supremacy

Nintendo doesn't play the specs game. For musclebound Sony and Microsoft, though, it's an unavoidable clash with every new generation of hardware.

Eurogamer's well-regarded Digital Foundry blog reported a comprehensive rundown of the Orbis hardware a month ago, claiming that it would pair a 1.6GHz eight-core AMD processor with Radeon HD graphics hardware. The processor is said to be based on AMD's low-power Jaguar architecture, and will reportedly make an appearance in Microsoft's next-gen console — widely known as "Durango" internally — as well.

So how powerful will the PS4 actually be, and how will it compare to Durango? Digital Foundry pitted the two hypothetical consoles against each other, and found that Orbis "looks the tighter, more powerful, more games-focused design" thanks to a beefier GPU and faster RAM. Clearly, that comparison is based on a lot of hypotheticals, unknowns, leaks, and rumors, but it's something to get the warring factions started early. Regardless, it's safe to say that both will easily outclass the Wii U in raw performance.

Now it's time for Sony to execute

The two most important figures for many — price, and release date — probably won't be revealed this week. There's almost a full year to go before the suggested holiday launch, and a lot of things can change in that time — not least Microsoft's own entry. A late 2013 release in North America and Japan seems a safe bet, based on history and reports; Edge and the Wall Street Journal have both reported as much (the PlayStation 3 slipped to a spring 2007 release date in Europe following a holiday 2006 launch elsewhere), and Kotaku suggests a November launch. And according to the Asahi Shimbun the system will launch for over 40,000 yen in Japan, which if true would suggest a US price of at least $399.99 even with the most optimistic exchange rate interpretation. Kotaku says there will actually be two models, tentatively priced at $429.99 and $529.99 respectively.

We're unlikely to learn absolutely everything about the PlayStation 4 tomorrow, then, but at this stage one thing's for sure: Sony's banking on this product — and the entire ecosystem that will congeal around it — to spearhead the Japanese giant's turnaround. The execution will need to be flawless for Sony's ambitions to stand a chance.

Sean Hollister, Andrew Webster, and Chris Ziegler contributed to this report.