If you're a role-playing game fan, this is not a game you'll want - or honestly be able - to complete in a weekend. After logging almost 20 hours, I've just now hit the meat of the story. The developer BioWare claims the game will take 40 hours of play, and that's for people who play right through without exploring.

The story is rather generic sci-fi fare. Humanity has become an upstart player on a galactic stage in the 21st century. We've butted heads with a few alien races but we're allowed to join what amounts to an alien United Nations. Humans have made some enemies on their way to the top, and one rather vicious alien, Saren, is out to wipe us out with an army of killer robots called Geth. Your Commander Shepard is called on to stop them.

I say "your" Shepard because you can quite literally make the protagonist look almost exactly like you with the character creation tool. The level of customization, from combat ability and sex to even military and civilian background, really anchors you to your character.

This level of interaction goes even further when you start playing the game. The core of "Mass Effect" isn't so much the combat but the conversation. There are hundreds of unique characters you can talk with to advance the story or just for idle chatter. Each one offers branching dialogue options that let you customize Commander Shepard's persona. Is a space port security officer giving your Shepard the business? You can play nice and ask her to calm down; you can pull rank and tell her to stow it; or you can just pull a gun on her.

Options like these pop up for nearly every character you encounter, and there are a few thousand of them. As you gravitate toward paragon or renegade, the game's definitions for good and bad, your reputation will actually help you. If you end up as a ruthless commander, you can intimidate people for money or information and people will treat you differently than they would a charming, law-abiding Shepard. Of course, you can always just play the middle and remain neutral.

All engagements are over-the-shoulder, third-person affairs in which you control yourself and two other squad members. I use the term control loosely because you can't hop into your buddies' shoes and tell them exactly what to do. Rudimentary squad controls such as "cover" and "attack target" help, and at any time you can halt the action to select which abilities they can use, but you can't control where they seek cover or when to help you. If left alone, the squad member's artificial intelligence jumps from taking care of you and itself to wasting power-ups and getting its head blown off.

The game's "spells" are sparse and most are shared between combat classes. The game's uniqueness takes a dive here as most telekinesis abilities just do the same thing - toss your enemy around - and the other stats you can upgrade as you level up simply revolve around how much damage you do with a certain gun or how much damage you can take. Classes such as the engineer are better for cracking safes and disabling electronics, but if you know how to use the game's rudimentary cover system, and have a decent aim, any class will perform well in a firefight.

When you break into the wider universe, the options start to open up. I've run across a few dozen galaxies so far, and each one has at least one, sometimes up to four, systems which in turn have four to six planets to explore. Most planets are just fly-bys that reveal atmosphere density and other inane info, but at least one will be explorable. Ground action is mostly a treasure hunt in a heavily armed moon buggy, but that's not really a bad thing. I spent a good hour on one planet uncovering a pirate stronghold and searching for lost artifacts. The planets that actually advance the plot will have more meat to them, usually a town or outpost to explore.

The graphics look about as good as you'd expect on the Xbox 360. There's nothing really flashy and most of the terrain looks like the moon but tinted yellow or brown. There are a lot of texture pop-ins that get annoying. Load times are another hassle. Prepare to ride the future's slowest elevators - "Mass Effects'" not so subtle way of hiding the loading screen.