Gabe Newell: The original Half-Life took us two years to develop. With a considerably larger team Half-Life 2 took us six years to develop, so we thought if we were going to continue our trend with Half-Life 3 we would basically ship after we had all retired.
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Probably a better name for it would have been Half Life 3: Episode One, but these three are what we're doing as our way of taking the next step forward, but Half-Life 2 was the name we used.