Not completely functional, because after the first game all the textures were glitched. I like the game though, and I'm leaving 4 stars because I think with improvements this could be a good extension.

this is the best chess i have played!

NOT A LEGAL EXTENSION! THIS EXTENSION COPIES A 1989 NINTENDO OF AMERICA GAME CALLED THE CHESSMASTER!

A great add-on for playing chess whenever you want. Replying to "it just being a picture of a horse", the problem might either be that it is keyboard-based: the mouse doesn't do anything in this add-on. Or it might be that it sometimes crashes. That's quite a big problem. When that happens, I remove it and add it again, and all should work. The settings for the keys are found at Add-ons manager > Chess (preferences).

It is LITERALLY nothing but a picture of a horse and some crappy music.