As far as I know, it was just this multiplayer shooter-type game made by Midway that took place on a Grid. It was probably like a first-person shooter death match, but I don't think it was first person.
Anyway, the only connection it had with MK is that they threw in a few of the MK characters as secrets, but it wasn't even close to being an MK game. Think of it like playing as Raiden in NFL Blitz.
I think it came out somewhere within a couple years after MK4 came out, 'cause the character models they used looked to be from MK4.