Excellent!

The fuel and overheating bars added a lot to the game, and the addition of the complete "Fighter" AI gave the player something to work with (or against).

I don't see the point in sending messages to other robots, or checking for "friends", because you can't make team battles.

For everyone who doesn't know how this works...
The Interface:
At the upper-left, there are two green arrows pointing to an empty tile. That's where the flow of the program starts. You can add to the flow by adding in the empty subroutine (the gray square with a - sign through it) and ctrl+clicking on it to create a green arrow pointing to the next subroutine.

Some subroutines do things (like the "self-destruct" one, or the "shoot primary weapon" one), and others check conditions (like "Check for an enemy", which is a very important one). For an action subroutine, just use a green arrow to continue the flow after it is run. For condition-checking, if the statement is true, then the flow follows the green arrow. Otherwise, if it is false, then it follows the red arrow (which you can place with shift-click).

At the end of the program, use a green arrow to redirect the flow back into one of the blank tiles on the outside (the ones on the border, with a chain of green arrows).

Then save it and put it in for battle. If you still don't know how to program it, then study the Stalker cpu.