I understand what you're saying and it is one way to provide challenge and balance to the game. However, IMO, I think it's going to lead more to players being frustrated at having to divide their attention. It's like trying to play Hide and Seek while at the same time playing Hot Potato. The way to find out for sure, of course, would be to try the game on a bunch of people that haven't played before, tell them nothing about any strategy for playing, watch them play and see what the result is.
If you want to keep it a two player game, I recommend trying out a few experiments on NPC movement to see how it effects your game play. It appears you're currently moving the NPCs randomly every turn through a loop. I wonder how the NPC behavior would look if you set it so that he has a 1 in 6 (or whatever) chance of being allowed to move at all? Or what if the NPC has a similar chance of moving in the same direction as he did last time? Is it still just as easy then to pick out the human players? Maybe it'd be an improvement maybe not, I don't know.
If you're happy with the way the game is, that's cool. I'm just assuming that by posting here you're looking for a bit of a critique and suggestions for improvements.
Edited by kseh, 13 July 2012 - 04:36 PM.