Unfortunately, I can't hand out keys for the original at this point in time. It only was free as a limited time offer if one purchased the remake on itch.io when it came out.
It's a deprecated version that can really break the save folder for the remake if not handled correctly (using backups and avoiding the Steam cloud). I consider it more of a museum exhibit of the project's origins as everything in it is of much lesser quality than the remake, and the current fee is only symbolic to avoid giving away the entire plot to anyone and everyone for free just yet. Even if the remake went through several revisions to bring it up to par, it would be difficult to convince people to purchase an upgraded version when there's a totally "free version" out there, despite the fact it's inferior in every way.
If you're interested in it but would rather not spend anything, I do plan on making it free eventually, perhaps when the entire franchise has concluded and I'm less bothered by the free-version situation. That is a fair ways off, though.