Loading up a section of what amounts to the third level of BioShock, Levine set the scene. The player has progressed to an area of Rapture--the underwater world where the game takes place--in which a forest, dubbed Arcadia, was grown as a sort of tourist attraction. These plants double as the city's oxygen production center, and now Rapture's Orwellian creator Andrew Ryan has released a toxin into the atmosphere which is slowly sapping the life of the trapped trees. The player first has to concoct an antidote to the toxins using the game's crafting system, but Levine proudly acknowledged that he had cheated. With the substance in hand, all that had to be done was to release the cure into the chamber. Fortunately for our purposes, the diabolical Andrew Ryan intervened at the last second, sending a swarm of genetically-modified minions to attack.

In one swift movement, the player ran straight up to a doorway and cut down the first incoming enemy with a gory shotgun blast to the temple. I was immediately taken aback. This felt more like a scene from Monolith's visceral Condemned: Criminal Origins (X360, PC) than a moment from a tactical shooter. Levine was quick to note that there are, of course, more intelligent ways of going about your business in the hostile world of Rapture. On queue, the player fired a trip-wire trap into a wall, and with another shot attached the second end of the wire to the opposing wall. The wire wasn't positioned effectively enough, so the player then switched to the Telekenesis plasmid. Plasmids are essentially magic powers, through which the player can cycle through as he would a physical weapon. Using Telekenesis, one end of the trip wire was snatched up into the player's hand and quickly replanted across a doorway. "We found out in testing that this worked," Levine remarked, alluding to the game's unpredictable nature. An enemy soon came barreling through the passage, the wire sending out an electric current and dropping him like a sack of potatoes.

These kinds of traps can be set in a variety of methods. As more enemies poured into the room, the player began rapidly using the Cyclone Trap plasmid, dropping swirling vortexes along the floor which instantly shot the mutants into the air like a rocket. Standing in front of a pool of water, a handful of wading bad guys were dispatched with a quick shock from the Electrobolt plasmid. Environments can often be taken advantage of in this way. An oil slick milling in a corner can be ignited with the Incinerate plasmid, the fire spreading realistically from end to end and torching everything in sight.

Machines are exploitable as well, both by the player and by the ghoulish Splicers. Passing a medical station, Levine noted the dual nature of the innocent contraption. "These will heal people, and if the enemies use them they can heal themselves. But not if you hack it. If you hack it, it will poison them," he explained. At this an enemy approached, running to the machine for a boost of health. The player ran for the machine, attempting to hack it before the monster had used it--too late. Another shotgun round covers up any trace of failure.

Hacking is a free, easy way to increase your odds of survival in BioShock. Vending machines can be hacked for discount prices, and stationary turrets can be converted to save on ammunition. As the player will often traverse one section of the game many times over, having a turret on hand to defend from roaming Splicers comes in handy. Once in close proximity to a hackable object, the press of a button begins the hacking minigame. The game tasks you with completing a series of pipes by swapping out various pieces before the flow of water catches up to the end, like a timed game of Rivers, Roads, and Rails. Often challenging, but not frustratingly so, the minigames are a pleasantly puzzling diversion.

With so many mechanics at work in BioShock, some fairly inventive scenarios can be devised. While enemies were slowly cutting through a steel door, a proximity mine was attached to a barrel and placed just in front of the doorway. Needless to say, the ensuing battle was short-lived. Flying attack bots can also be hacked and put to non-standard use. Attaching a proximity mine to an oblivious bot, the friendly machine runs straight into a swarm of enemies like a homing missile, exploding in a massive fireball. "That's nice," Levine cackled, still entertained by a world he has labored to create for years.

Some time later, the player managed to tether a flying bot to the ceiling with a wire, the bot bouncing back and forth in a futile attempt to escape. Wires can also be attached to Splicer enemies, the ensuing tangled mess leading to clothes-lines that take down other enemies as they run in circles. In a brooding, atmospheric game, the entertaining combat often transforms it into a dark comedy. "The best part is when you blow off people's hats and just toss them back at them," Levine said while, on screen, a little ingenuity transformed a teddy bear into a deadly weapon.

Continue reading for more details on BioShock's environments and teaching methods.

The enemies now defeated, it was time to head back to the forest. After using the antidote, the trees began to branch out and flourish, restoring oxygen to the city. While the combat can be intense, the draw of the game is rooted in its sense of atmosphere and exploration, with the interaction between the player and the environment serving as a driving force behind the story. In many ways, BioShock reminds me of Metroid Prime, and I wasn't surprised to find that Levine himself had compared it to the Retro Studios adventure-shooter in prior presentations. Exploring the dead world of Rapture is simply enchanting. Every neon sign and faded billboard is a crisp work of art, dangerously drawing your attention away from the path ahead. It is as alien as anything in Metroid, and as finely crafted.

While it is easy to become distracted, the action ramps up at a rapid pace in BioShock, and players will have to know their stuff to survive. Throughout the game, hints are doled out gradually, with the goal of teaching the player each of the game's many systems. While I was concerned at first that these tooltips would be intrusive, my fears were quickly assuaged. "I hate fucking tutorials," Levine told me. "We do very little telling you, 'this is how this works.' I don't think there are any quests designed to test repeated skill usage." To that end, if a player isn't using the correct ammunition to attack an enemy, or if he has cash on hand but no health, the game will drop a brief textual hint at the bottom of the screen. Pressing the back button while looking at an object brings up a related tooltip, allowing the player to request help at any time.

The game also teaches the player in more subtle ways. For example, in the first scene that the player is introduced to the hulking Big Daddy monster, his Little Sister companion is attacked by a Splicer. In response, the Big Daddy becomes enraged, dispatching the unlucky attacker. The player knows from that point onward that the Big Daddy will protect his tiny cohort by any means, and not to mess with them. This "show, don't tell" approach is a simple idea, but remains a breath of fresh air in a medium full of dull training levels and heavy-handed explanation.

Of course, it's not all about genetic powers; sometimes you'll have to pull out a Tommy gun and go to town, although the most satisfying strategy involves a combination of plasmids and conventional weapons. Zapping enemies with the Electrobolt momentarily stuns them, giving you an easy window for a point-blank headshot. The Winter Blast plasmid freezes them in place, with a quick shot sending the unlucky foe shattering to the floor in pieces. However, BioShock is set in an abandoned city, and ammunition must be carefully managed. More than once I found myself completely out of bullets and the "Adam" energy which powers plasmids, resulting in several deaths as I ambled around aimlessly. Scouring every nook and cranny for everything from bullets to potato chips pays off in the long run. Cash found on dead enemies and amongst dying scenery can be spent at automated vendors, which sell health packs, ammunition, and tonics that buff your abilities in various ways.

With a massive set of noise-canceling headphones wrapped around my head, BioShock's sound field immediately stood out. The clarity of dialogue was stunning at times, with soft voices slowly creeping up behind my ears. While I was never truly frightened in playing the game, the moody atmosphere was ultimately more interesting to me than any moment of real tension. Stepping into the Rapture for the first time, Trenet's La Mer echoing through the halls, I wasn't scared when the lights went out--I was more anxious to simply move on to the next gorgeous area.

In one early scene, the player is faced with an impassable block of ice. Later, an abandoned crematorium is found, with burning corpses and oil slicks littering the area. After finding the Incinerate plasmid, the player backtracks to the ice wall, melting the blockade and continuing onward. This brought to mind a similar sequence of events in Metroid Prime, and further connected the two games in my mind. The subtle story and need-based objectives, combined with backtracking and the unlocking of new areas with special powers all came off as reminiscent of the Nintendo series. Even the opening of doorways with a blast from the Electrobolt seemed an homage to the iconic, concentric doors of Metroid.

I had intentionally watched very little BioShock footage before going into the presentation. After more than an hour of playtime, I couldn't shake the feeling that despite the chaotic, bloody combat, the unique mechanics, and the entirely different setting, BioShock has more in common with a Metroid title than I had expected. From me that is high praise; not often does a shooter find that tricky blend of elements that provides a more fulfilling experience than your average run-and-gun du jour. With Metroid Prime 3: Corruption set to release literally a day apart from BioShock, late August is looking like a great time for gamers who demand a little more depth to go along with their gunplay.

Irrational Games' BioShock is set to be released in North America on August 21 for PC and Xbox 360. The game will follow in Europe on August 24.