Gamertell has posted its hands-on impressions of Mass Effect 2 demonstrated during CES 2010.
"To help amp up the action, Bioware worked hard on enemy AI. In Mass Effect, there were only a couple of AI patterns. Houston said different races of enemy now will fight according to their personality. The huge, powerful Krogans are going to take the opportunity to get in your face at close range. Less physically imposing races such as the Geth would rather trade gunfire with you. In ME2, there are as many AI patterns as there are different enemy types."