We’ve seen sentry guns before, working ones in fact, but this one takes a special place in our hearts… like everything Valve-related. This particular one isn’t a DIY project, though, it was put together by none other than WETA, famous for having done the special effects work in every movie, ever.
It seems Valve commissioned them to make the thing, and they’ve really come through. It’s solid metal, tracks you across the room, and makes a little noise. Or maybe it actually fires, just not lethally, since it’s just a level one turret.
Now they need to order one of the Portal sentries and have it give you a guilt trip when you when you walk by.