Character creation time.

Class: Vanguard — a shotgun-toting telekinetic warrior.

Background: Raised on the mean streets of Earth, joined the Alliance military to get out of the gangs.

Psychological profile: Ruthless, but gets the job done.

Scar: Across the right eye.

Name: Penis Shepard.

He may be a maverick renegade who plays by his own set of rules, but the bastard is the best hope we’ve got.

Or not. My suitemate’s character, Foxxxy Shepard, was raised as a hardworking colonist and has always been a shining example of service to humanity. Eschewing psychic powers allows her to focus on her assault rifle skills. Unlike Penis, who shoots first and asks questions later, she’s a master diplomat who’s able to talk her way out of almost anything.

This kind of moral dichotomy has always been at the heart of Bioware’s games, and in their newest sci-fi RPG “Mass Effect,” it feels more successful than ever. Your character is a projection of your noblest dreams and your cruelest fantasies. In the process, the galaxy Bioware has created comes alive, and you feel it shake based on every one of your decisions. “Mass Effect” is one of the best games on the Xbox360 and the best game yet to come out of the already acclaimed Bioware.

What’s so incredible is how “Mass Effect” is able to draw gold from what is essentially just generic sci-fi. You’ve got your super-advanced technology made by a mysterious race of long-dead aliens, a la “Halo.” You’ve got your ancient and nameless evil that destroys everything it touches, also a la “Halo.” You’ve got your impotent high-council of aliens too weak to take real action, a la any number of things. Finally, you’ve got your rogue hero and faithful crew who are the only thing that can save the galaxy, a la pretty much everything.

Despite this delicious mess of cliches, the galaxy that Bioware has created feels fresh, vibrant and new. The aliens don’t look much different from generic alien stereotypes, but those stereotypes are presented with such honesty and faith that they feel real. The voice acting is excellent across the board. The main character does sound flat, but that’s the nature of an avatar that is supposed to be more like a blank canvas than a fleshed out character. The characters and the world they inhabit feel so completely constructed that you feel a duty to protect them — or you take true sadistic pleasure in destroying them.

Like the critically acclaimed but un-fun “Jade Empire,” “Mass Effect” blends real-time action into a fully developed RPG. Unlike “Jade Empire,” the combat never feels separate from the rest of the game — you simply are commander Shepard, and sometimes you are killing things, sometimes you are not. The fighting itself may not be as refined as a full-on third person shooter like “Gears of War,” but it’s still clean. Using special abilities requires you to pause the action, which makes it tedious to play as a character that uses psychic or tech attacks extensively. Your squadmates can be set to use powers automatically, but they oscillate wildly between effective and idiotic. Still, the combat accomplishes the main task of combat in any RPG — its fun to use new weapons and abilities, and you get satisfaction out of kicking ass with upgraded characters.

The main story isn’t tremendously long — you can finish it in about fifteen hours if you hustle. But, like in the Elder Scrolls series, the main story is only a small part of the action available to you. There isn’t quite the infinite content available in Elder Scrolls, but the galaxy in “Mass Effect” is gigantic. There are nearly twenty nebulae, each with one to four star systems, each of which has at least one planet you can land on. There are usually a few other planets too, and every one of these hundreds has a brief description written by some poor, lonely intern. You travel around these uncharted planets with a mako, which is an ATV imbued with all the powers of a slinky and a gecko. The galaxy is scattered with besieged marines, ancient relics, valuable minerals, biotic terrorists and rogue agents — all of which are waiting for your benevolence or cruelty.

Of course, all of this wouldn’t really mean anything if the story weren’t as good as it was. The reason that “Mass Effect” is so successful is because it manages to lend weight and gravitas to every one of your actions. Not only is the thru-line of the main plot strong enough to carry the entire game, but also the world that Bioware has created is real enough to support that plot. For all the cliches and silliness you’ll find throughout the galaxy, you’ll believe every moment of it because Bioware has made you care.

Also, Seth Green plays your pilot. Can’t touch that.