A port of the original Doom game was released in Flash!

But let me explain that: It’s not just an ugly random remake… it’s a FULL PORT. Well, except for the music (at least for now).
It uses a Flash 10 tool that apparently allowed the Doom Flash creator to compile the original Doom C code, which is very interesting for game developers.
So, what you’re seeing here is a true port of the original Doom game.
Just click the image or the link to Newgrounds Doom page and check yourself to understand what I’m talking about.

Source: Kotaku