There's a thread posted by @O Ilusionista, but I'm uploading the game to keep it here as well.
I visited the Heat-Games page and saw that they have started another project DEADPOOL PROJECT _ MAXIMUM CRAZY which is announced on their page. But it seems they haven't finished it in recent years.
Additionally, the YouTube and Internet addresses they left behind have been deleted.
So I think the link posted by @O Ilusionista is one of the latest sources to download the game.
For this reason, I think it's a good idea to save a copy of it here on the OpenBOR forum before this link disappears.