Valve's Doug Lombardi told us they'd be showing off new levels and gameplay mechanics at E3, hopefully with the user-controlled boss section in full effect. The bosses you can control in that mode are: The Boomer, a huge fat zombie that, upon his death, sprays sludge everywhere; The Hunter, a spider-like monster that requires some teamwork to take down; The Smoker, a creature with a fifty-foot tongue that leaves the room in a haze of smoke; And The Tank, a massive beast which, much like The Hulk, puts up a struggle before submitting to your control.
Valve has added a split-screen mode on the console version, enabling you to play with a buddy locally, or online, with two linked pairs making up the "4" in Left 4 Dead. Naturally, tou can also play in an online campaign mode that allows for one to four players. It should be noted that within "Drop In Mode," an A.I. bot immediately takes over for a player who has dropped out. If said player returns to the game later, he or she can jump back in and replace the bot. Hopeful hooray for no Halo style-lag screens when someone decides to quit out of frustration!
As Randy mentioned, the game relies heavily on squad-based gameplay -- you have to constantly watch your teammates on screen to see if they need help or reviving. The game has a vision tweak that allows you to see your teammates through walls as silhouettes of their profile. They're green when all is clear and turn bright white when they're in trouble. It replaces a tradition on-screen radar and keeps your eyes centrally focused on the action. Valve's Michael Booth admitted, "It's a little gamey, it keeps you there. Like in the real world if we're in a building together, I'm going to hear you around the corner and know where you are. We wanted to eliminate the radar and keep it simple."
We'll spend more time with Left 4 Dead at E3 to see what new stuff Valve has in store, but right now, it's shaping up to be a quality horror game with an impressively integrated multiplayer component.