I'm 99% certain that 1.0 was released to Steam, and all official versions since as well. 11 years ago today.
The CE was the only physical version released, under arrangement with a different distributor, and I believe that was version 1.1 as well. The box included a Steam key so that it could be updated. There are still a few of those popping up on internet stores these days, though Re-Logic's association with that company ended long ago.