What's the best way to kill armored soldiers in Blood Dragon?

Solution 1:

At level 15, you get the "Heavy Beatdown" ability, which allows you to use melee takedowns against heavies. I seem to remember after this point being able to just jump around near them, mashing the takedown button until I got the "aerial takedown" prompt.

Before you've hit level 15, you're better off aiming for the head. The flamer heavy guys can be shot in the tank to cause it to catch fire and explode. The minigun guys have a tiny weak point around their neck, which can make them vulnerable to arrows if you can hit them just right. Otherwise, you're right in that knocking their helmets off is the fastest way to kill them.

Solution 2:

I prefer to to stun the using grenade only if you are low on level. Then Aim for their heads. Also, 2 grenades are enough for knocking them down.