Like Aielyn stated, the A.I. was toned down and invincibility enabled. This is a common practice for preview builds and game conventions (at least the A.I. part is).
I've written dozens of hands on impressions for E3's and I always have to remind myself that the A.I. was toned down for the event and sure enough it's almost always more aggressive in the retail build.
The rEVOLution is not being televised







