A few basic questions

You have an interesting point. The 3D by itself already makes the game fairly complex. However compared to the original version it has been greatly simplified.

Currently the radar is an 'all seeing eye'. It can't see bullets, but I could see it being blocked by a robot, since missiles are 1/3 the size of the robots that fire them. So an enemy could fire a missile opposite of the enemy, cover it till it stops and then lure the enemy towards it, or wait for them to approach it, and reactivate it, or possibly several to flank an enemy with mines.

That actually sounds awesome, and as long as missiles/mines are not one hit wonders, it should work wonderfully. I think 8-16 damage (4-8 to fire), with a limited fuel supply is best. I don't want it to overlap with bullets, which at the moment cost 0.5, and do 2 damage.

Though I think limiting the number of active missile a robot can have might also be an good idea. But that requires a way to disable them, or rather remove them from your control so you can fire another. But perhaps they could still work as passive mines.

On the note of missiles, since they can navigate. I think you should be able to hit yourself with them (after a few ticks to activate).