One of the most anticipated titles at E3 was Bioware's next-gen action RPG, Mass Effect, which is coming exclusively to the Xbox 360 in 2007. Mass Effect is all about size and scope, and the demo level we saw, "The Citadel," was of an expansive futuristic city that featured a massive docking bay for large spacecrafts. There was a rich use of color throughout the level and some incredibly impressive lighting effects. The lighting really stood out as looking "next-gen" and quite realistic, complete with the blending of different colors from multiple light sources on the same object.

Adding to the sense of realism were the NPC characters in the environments. Loads of NPCs filled the hallways, bars and other areas of the city, and they are all showing off their dynamic AI by doing things on their own and reacting to things around them in a very natural and unscripted way.

As the demo progressed, Jay Watamaniuk of Bioware showed off the squad of playable characters, headed by Commander Shepard. While he was the main character in the demo we saw, you can actually build your own via the game's in-depth create-a-character system. You'll also have the ability to recruit your own squad members as you make your way throughout the game. Exactly who you pick to be in your squad will have a profound impact on the other NPCs in the game. Each of your squad members will have his or her own unique personality and interact with both enemies and friendly NPCs differently. Some will be really aggressive and charge into battle or be very candid when speaking to a non-enemy NPC, while others will be more passive and not react as strongly to things.

What governs this is Bioware's brand-new dialog system that uses emotions to express feelings. Unlike Knights of the Old Republic, where you selected your answer from a set of canned responses when talking to NPCs, you pick from a range of emotions. When speaking with an NPC, you now have the choice to select from a strong response, passive-aggressive, or other options, like talking your way through the matter. Once you select one of these, your character will then reply with dialog based on the emotion you selected. You don't actually know what your character will say before he says it; all you know is what sort of emotions he will be using when speaking. This really helps create a much more realistic and compelling gaming experience, which is also boosted by the main character and his squad actually speaking with their own voices instead of replying in text (again, like KotoR).

Getting back to the "size and scope" theme of Mass Effect, the galaxy map displays tons of smaller solar systems with stars, planets and moons that can all be explored. We couldn't get any specific numbers, but from what we saw, it appears that Mass Effect will literally be quite massive (pun intended). You can go to any of the available planets, moons or asteroids, land on their surface and start exploring. You even have access to a surface rover that you can use to drive around the new world, and as you progress through the game, you can upgrade this vehicle with more features. While the standard number of completely different and unique planets to explore is already stunning, even more will be available for download through Xbox Live.

The demo wouldn't have been complete without a look at the squad-based combat, and we saw a level in which you'll be clearing out the baddies in an abandoned city that has became overgrown with vegetation. When you encounter enemies, you use a target lock-on feature to engage them in combat, which utilizes a third-person, over-the-shoulder view. Unlike the KotoR series, the combat here is real-time, and once you're locked on, it is quite fast-paced and intense.

The enemy AI, as well as the AI of your own squad, appeared to be quite smart. We saw many examples of the enemies taking cover and popping out to take a quick shot at us before heading back behind cover. Other enemies would lay down suppressing fire to make things even more difficult. To counter this, you have the ability to give orders to your squadmates and even direct them to specific locations on the map. Mass Effect uses an on-screen menu system, much like the one in the Brothers in Arms series, where you can select a squadmate and move an icon across the level to wherever you want him to go. You can have your team members flank and take cover behind objects, as well as many other tactics. This really added a great layer of depth to the combat system, but in true Bioware fashion, it did not add any extra complexity to the game, thanks to the simple-to-use menu.

When all was said and done, we were left quite impressed with Mass Effect. The level of detail in the graphics, especially the facial expressions and lighting, screamed pure next-gen. The gameplay itself was also very impressive, and it seemed to strike a great balance between that of the KotoR series and a true third-person shooter. This was a very early demo, and the game is not due out until 2007, but given Bioware's excellent track record, Mass Effect will likely redefine the term "epic."