In the first 5 mins the Reapers invade Earth and blow the hell out of London, Washington, and most of the planet. Not only this but I get the feeling Shepard is starting to go a little bit nuts after fighting the Geth, Collectors, and now after what I can only assume is pretty bad concussion.
Even if that wasn't a good enough tutorial for anyone wanting to get into the series then and there they send you to Mars to find one of your oldest allies. To top it off you get told that Cerberus is now *** with the Alliance as well. Even more so that now these Humancentric fellows are doing wierd and whacky things to their own men which make them look like the Reaper's Husks.....
Oh and then they dramatically have one of your crewmates incapacitated by some robot thingy.....
What will happen next? (THIS IS A RHETORICAL QUESTION, IF ANYONE POSTS WORSE SPOILERS THAN THIS I WILL BE VERY UPSET!)
Also the whole game has just been tuned up perfectly IMO. Guns feel like they do damage, biotics look destructive (Warp looking like it is burning them alive in blue fire), and the menu's and graphics are amazing.
Now I know what people say about Bioware but at first glance they have done a hell of a job.