Imagine being Dexy's Midnight Runners, circa 1982. "Come On Eileen" just came out of nowhere and is blowing up. It's on every radio station, and playing at every party. Nobody had ever heard of you; now you're everywhere. It's awesome, you're famous, drugs are probably involved—but there's something in the back of your head saying "how the hell are you going to top this?"

That's what it's like to be OnePlus right now. The upstart smartphone manufacturer launched out of total obscurity a little over a year ago, and immediately won the hearts of Android enthusiasts. The company's first device, the OnePlus One, was a geek's dream: It ran CyanogenMod, it had killer specs, and at $299 unlocked it almost seemed too good to be true.

Today, OnePlus is launching its second device, the OnePlus 2. It's an upgrade on the original in a number of ways, with a brighter 5.5-inch, 1080p screen and a (supposedly) massively improved 13-megapixel camera. (Neither spec has changed, but the implementation has—these are the advantages of a second generation.) It's a flagship phone in every sense, with 4GB of RAM, Qualcomm's new Snapdragon 810 processor, and a fingerprint reader. It runs OnePlus's own OxygenOS, which is for the moment just a lightly-customized version of stock Android plus an additional home screen populated with your most-used contacts and apps. The battery will last at least a day, though co-founder Carl Pei cautions it might not last as long as the One. It's powered by USB-C, and along with the phone OnePlus will be selling a nifty red charging cable that's reversible on both ends—even in your old-school USB port.

It starts at $329 for 16GB of storage, and runs up to $389 for 64GB. If you're counting, that's a little more expensive than last year's model, not that it bothers Pei. Price isn't the point, he says; he hates that people think of his company as just a cheap smartphone maker. He just wants to make a great phone.

OnePlus doesn't care about being cheap—just about making good phones.

A year ago, making a great phone was a serious achievement. A few users complained about the One's screen defects, and more objected to a terrible, sexist ad campaign the company ran. But it was, by any metric, a smash hit. When the phone launched, OnePlus had 1,000 in stock. Their metric for success was 30,000 phones sold. They've since sold more than 1.5 million. This time, things have changed. It's been 458 days since the One dropped. The company has exploded in size, up to 900 employees. There may have been no pressure on the first phone from an obscure Chinese company, but there's plenty now.

As he talks about the 2, and the year OnePlus spent building it, Pei is visibly both exhausted—that might be the jet lag, since he'd just gotten in from Shenzhen, China—and nervous. The day before our conversation, the phone had leaked thanks to a Chinese certification agency, and the feedback was brutal. People hated the look of the new model, which Pei seems to have only half-convinced himself is because the pictures were bad. "It's not ugly, right?"

It's not ugly. The metal body's a little bland, maybe, but no more so than your average handset. Its design is simplified and toned down from last year's model, so that its four different covers—made of bamboo, rosewood, black apricot, or kevlar, in addition to the textured black from last year—are the source of most of its aesthetic differentiation. "It's a more timeless design," Pei says. "This one might not look as pretty the first time, but it really, really grows on you."

The 2 is almost certainly a better phone than the One, and its upgrades are smartly identified and appear to be well-executed, but there's nothing at all splashy about the 2. There's no headline-grabbing feature that would guarantee OnePlus the same kind of attention it got last year. Lots of companies make great phones at low prices, many of them much cheaper. OnePlus has to contend with the fact that it's no longer the sexy upstart—it's just a phone maker.

Is a good phone enough to help OnePlus stay exciting?

Granted, it's a phone maker with an unusually devoted fanbase. Pei says he's been contacted by carriers in Europe and elsewhere, shocked by how much more data OnePlus owners consume than others. Companies like SwiftKey have told him that One users spend more money than your average Android user.

That has instilled some confidence within OnePlus. They're implementing an invitation-based buying system similar to the One, but this time, with "30 to 50 times" more stock on hand, waiting times should be much shorter. And as the company ships units and grows its user base, Pei and his team are thinking about what it means to have two, five, 10, 100 million people using your hardware and software. Pei likes the idea of selling hardware at tiny margins, and using your reach to sell your customers more things, like Amazon does with its Kindle Fire tablets. "If you control the OS," Pei says, "you can have in-OS purchases." Maybe, he thinks aloud, you could let people pay for Dolby audio customization. He becomes particularly animated talking about what it would mean to gamify the software, to turn OxygenOS into the real core of OnePlus. "What if you can take an Uber," he asks, and after you take an Uber, you get a reward by OnePlus?" He calls this "mind control," before backing away from such a loaded term.

Bottom line, he's fascinated by the idea of what OnePlus can do when its audience is both captivated and enormous. "When you have a platform of 100 million people, you can do a lot of positive things for the world."

"We have our own vision of how we want our operating system to work in the long run," he says, "but we can't push it onto our users. We have to slowly introduce it to them, because a lot of them are still really used to the Google ecosystem, where they want the stock Android experience. But I'm sure in three to five years Oxygen will look really different."

At that point, he's not even sure if OnePlus will still be a phone maker. Pei says the company's interested in making whatever product people primarily use to connect with the Internet; right now, that's smartphones, but it may not always be. (Pei's vote on what's after: contact lenses.) OnePlus only wants to make one device at a time, and to do it exceptionally well.

That's why, even though the company built two smartwatches that it planned to launch alongside the OnePlus 2—one a fitness tracker made with bamboo and an LED watch, the other much more like a high-end wristwatch—they scrapped the project. "I think the smartwatch is never going to become the core device," Pei says. Though he seems able to imagine the OnePlus 8 as a contact lens that connects to the Internet...

For now, however, we're still on the OnePlus 2. Starting today, the company makes its first move since its hit debut—and try to make the precarious move from one-hit wonder to next big thing.