I've been playing a heavily modified version of FNG solo. Having a good time with it, I decided to make an AI deck to control the enemy.
That's how the Hostile Tactical AI deck was born.
It's a deck of 72 cards that program the enemy, so you can fight solitaire or co-op. It's designed for games with ranged combat. The rules are really simple to allow it to be used with many different systems.
Don't know if this is allowed, but it's available on thegamecrafter.com
How it works:
When an enemy unit activates, you draw a card which orders the enemy unit. Multiple cards are drawn to tell which direction and how many inches the enemy travels, or who it attacks. Sometimes it flanks, other times it will move defensively, or other times outright charge!
It's not brain surgery or rocket science, but for a solo competitor it puts up a good fight. The rules are also setup for unaware units for stealth missions.