Jensen can employ cover -- now something players can set to toggle, based on some feedback Eidos Montreal received after the last set of previews. By sticking to walls, boxes and sneaking under some trucks, Jensen's infiltration of the building almost looks easy, until he reaches a door requiring keycard access.
Hacking is a major component of the game, and appears in the form of a mini-game where nodes must be captured before a sub-routine captures your user node. It's not as complicated as it sounds: you pick an icon, choose to hack it, then wait. Time to hack is based on a number corresponding to the difficulty of the node in question, and you're given a bonus should you capture the enemy user node. During this segment, Jensen earned a pair of viruses which can grant you instant success in hacking or slow down enemy users in the system.
The catch is you can't do everything all at once. Though Deus Ex may look and play like a first-person shooter with cover mechanics, there's a heavy emphasis on character development. This isn't Crysis where you can swap between stealth and armor at will. Instead, the choices you make stick with you. As protagonist Adam Jensen you modify your body and your gear in according with how you want to play.
About six to 10 hours into the game, you'll have filled out enough of your skill tree to see a significant impact on gameplay. Taking the stealth approach can be an effective way to navigate dangerous areas, but costly. Remaining cloaked consumes Jensen's energy, which doesn't automatically recharge to full capacity, meaning the cloak ability can't be spammed. Instead, it'll need to be mixed in with careful movement around stages swarming with enemies. You'll need to keep an eye on the directions enemies are facing as they patrol, as their ability to detect your presence is based on line of sight and sound.