Sony Ericsson’s Android-running PlayStation phone, the Xperia Play, finally became an official thing when it was announced by an ad during the Super Bowl. Sony hopes the device will find an audience between die-hard PlayStation fans and the more casual mobile gaming market that has exploded in the last two years.

At Game Developers Conference 2011 in San Francisco this week, I got a chance to sit down and spend a few minutes messing around with the Xperia Play, which included sampling a couple of its games and testing out its slide-out gamepad. And after spending some time with the device, I must say that as far as mobile gaming is concerned, Play could easily become the device of record and a new benchmark in the industry.

My time with the Play specifically concerned the slide-out gamepad, and I wasn’t able to figure out how to quickly switch the device back to touchscreen-only for the games I was playing. I got a few minutes with Bruce Lee: Dragon Warrior, a fighting game, and Star Battalion, a dogfighting game in which you pilot a space ship from a third-person perspective.

As far as the gamepad is concerned, it really feels great. The buttons are responsive and feel good in the hand, and Sony Ericsson has done well with their design choices to make it fit your grip well. The company has succeeded in creating a phone that feels like a dedicated gaming device, like Sony’s PSP — the buttons don’t feel cheap, and the gamepad doesn’t feel slapped onto a phone. This is an integrated, fully functional and well-planned piece of hardware.

The Play perfectly addresses one of the major issues with a lot of mobile games: it eliminates the need for virtual controls, giving you full access to the phone’s entire screen. It also gives players the benefit of tactile controls over imaginary ones on a screen, and that just makes the player play better — it’s a lot harder to blame the controls for causing you to lose a game.

The controls are very well integrated into the games, too, at least in Star Battalion and Bruce Lee. Gameloft, Star Battalion’s developer, has already gone public with its support of the Play, so I’m not sure how well other games will utilize the hardware right out of the gate, especially if they weren’t designed with the Play’s gamepad in mind. But for Star Battalion, the control scheme was phenomenal, highly responsive and pitch-perfect for the mobile game.

There’s also another set of controls on the Play’s gamepad: a touch panel that’s meant to emulate two analog sticks like one would see on a console video game controller. In a word, they’re weird, and I had trouble wrapping my brain around how exactly to use them. The touch panel, which has raised rounded edges around the analog stick parts, is supposed to be treated as if you’re imagining your thumbs are on top of the sticks and you’re pushing them forward and back — just like on a console controller. But the fact that you’re not actually putting your thumbs on sticks makes the touch panel a whole lot less intuitive than it means to be. It’s a feature I’m not sure many players will bother with, given the much better directional pad just above it.

Combining the innovation possibilities of the Android touchscreen with the slide-down gamepad, which completely improves virtual controls, Play could very well be the device that defines mobile gaming, provided it finds a market willing to purchase it and give up features like a slide-down keyboard. The device’s success very much hinges on whether it can find a group of mobile gamers who consider themselves gamers enough to go for a phone dedicated to that application.

It’ll likely depend on a few important things on Sony’s part — marketing, principally, and a competitive price that will put the Play in front of a lot of potential customers. That will mean identifying a marketing strategy that’s going to find people who like playing games on their phone, and showing them that they can do it better and have more fun. That’s really the strength of the Play: the benefits of mobile gaming and touchscreen capabilities, coupled with a much better way of playing games in general. It’s a fun device for Android owners, but it’ll take Sony Ericsson working hard to make people aware of how much fun they could be having with this phone over others.