I don't know if this is a re-post but i stumble across worlds smallest size first person shooter known from a German developer. I ran it on my computer and it runs pretty fine. I can't believe it for 96KB something it can pack so much graphics. take a look at it by your self.
It is called "kkrieger"
http://www.theprodukkt.com/kkrieger#20
It is called "kkrieger"
http://www.theprodukkt.com/kkrieger#20