Take2 made it, therefore it is an official plug. It is sorta 50% plugin & rest totally different. Probably if it were a plugin it would be 400mb to download hehe.
Looks really good too. Only $19.95 but Myth Codex costs that much too.
When I was at Software Etc. a couple weeks ago, I saw that. It says right on the front of the box that it uses the Myth II gaming engine. The screenshots reminded me a lot of Myth II, but there are a lot of differences, at least according to what it says on the box.