He reiterated that Tomb Raider was the fastest-selling game in the history of the franchise and said it was the "most critically acclaimed title" ever produced by Crystal Dynamics.
Despite the sales milestone and critical plaudits, the game failed to meet Square Enix's sales expectations. Crystal Dynamics is currently working on a sequel for next-generation consoles.
Gallagher also revealed in the blog post that 2010's digital-only Lara Croft and the Guardian of Light has now sold over 1 million units across all platforms.
"This represents a great landmark for a digital-only release," he said.