The last scene that we got to see was the most powerful, and impressed upon us just how deadly Shepard's new mission is. The Normandy, Mass Effect's home vessel, was under attack. Shepard ran through the fiery corridors as the camera cut away to show the craft smoking and flaming (and, eventually, breaking in two). Shepard and his companion made it to the escape pods, but our protagonist had additional priorities. He climbed stairs to an exposed deck. The sound muffled, and we heard his heart beating loudly from the speakers. We watched him approach Joker, still seated in his navigation seat, unwilling to desert the Normandy. Shepard lifted Joker, but the exploding Normandy propelled them into space. This choice had disastrous consequences for Shepard: The soundtrack slowed, and we watched him float through space, apparently doomed to be simple space debris. BioWare confirmed that your choices can lead to Shepard's death, which drove the "suicide" part of "suicide mission" home.
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Mass Effect 2 is a visual stunner. The city vistas that showed the sun filtering through the building are awe inspiring. The cinematic cutscenes are better than ever. And, best of all, I didn't notice a single bit of slowdown or texture load issues through the entire live demo. From what I saw, there is no reason to believe that this sequel won't surpass the original in just about every way.