Left 4 Dead 2 had "3.5 to 4" times as many pre-orders as L4D
Valve's Doug Lombardi has said that Left 4 Dead 2's pre-order figures "look to be between 3.5 to 4 times the size of L4D1's", contributing some of its success to the bonus baseball bat pre-order incentive.
(Industry, Left 4 Dead 2, PC, Xbox 360)