I'm really confused. How do I control this?

Tried on multiple browsers but it seems something is wrong here. Can't control anything and nothing seems to happen save for the knight walking back and forth swinging his sword and occarionally shooting beams out of it. Sometimes "-20" will pop up but after about 10 minutes I cant seem to work out what that means or if it is doing anything either. I switched from my chrome to firefox just to make sure it wasn't a problem on my end or something but it seems like something is missing here. It looks beautiful however so I'd love to see what this is actually supposed to be.