I was lucky enough to spend some time chatting to Gregory Zeschuk, President of BioWare, and he was obviously enthusiastic about the branching nature of Mass Effect. He told me that there are at least three completely different endings to the game, and it should take the average player around 25 hours to reach one of them, assuming that they choose a direct route. Greg was keen to point out that once you have completed the first section of Mass Effect, the universe really is your oyster and there are many, many planets to explore which have little or nothing to do with the main story line. I get the feeling that the hardcore players will be trying to complete every side quest as well as the main story, just like in Oblivion.
Mass Effect employs Ageia's PhysX engine for in-game physics, and from what I saw it's very well implemented. The Mass Effect world seems to react as it should to your interaction, rather than throwing up physics eye candy. Obviously you've got the usual debris being blown all over the place when there's an explosion, but it's not over the top, making the physics implementation an enhancement rather than a distraction.
Going back to visuals, it's not just the facial textures and animations that look good. The environments are well rendered and add atmosphere, especially when you're exploring new planets. There's good use of motion blur and even some film grain thrown in for good measure - the latter can be switched off if you don't like it. Most impressive though, is the depth of field effect, making it very easy for the player to concentrate on the focus of the scene - in fact I'd say that the depth of field in Mass Effect is the best I've seen in a game.
BioWare hasn't just concentrated on the graphics though, the audio is every bit as impressive. The music is especially great and any Blade Runner fan will feel right at home - the score is almost like an extension of Vangelis' classic soundtrack. Greg assured me that it was pure coincidence that Mass Effect will be launching around the same time that Blade Runner: The Final Cut hits the streets.
Mass Effect is due for release on 23rd November, which gives the Xbox 360 even more ammunition on the run up to Christmas. With games this strong hitting the street before the end of the year, I can see Santa delivering a lot of Xbox 360s again.