Surprisingly great!
I was not interested by this much as it was just a guy communicating with a robot in a rather mundane way (especially for a robot). It definitley got better as it went on and it helps that the animation is so good. The tone is really creepy and sets the atmosphere well. This reminds me of a Creepypasta, but turned into a flash cartoon. It ends so well, you simply have no idea what is going on and probably never will. A really mysterious factor is a great way to make something scary and few flashes here do scare me.