Valve have released an interesting figure for the original Portal; nearly four million copies of the puzzler have been sold, excluding Steam sales. We’re not sure why sales from the developer’s own digital service have been left out but they’re likely to raise that number significantly.
The original Portal was available both by itself and as part of The Orange Box, the bargain bundle from 2007. Given the near flawless critical praise its sequel is getting, you can expect sales to beat that of the original. Cake for all!