You see, it's a stealth-based game, or at least, that's one of the ways you can play it - turning on your cloaking field, dodging from group of plants to group of plants, shooting a dude in the back of the head with a silenced rifle. That bit's pretty fun.
Maybe you get spotted. Whoops! Go dodge between some bushes, they'll lose track of you pretty fast. That bit's also pretty fun.
And then there's a helicopter.
If the helicopter sees you, it will follow you. Forever.
You can hide in a bush. Technically, it can "lose you", and then it stops firing at you. But it keeps following you, no matter where you go. If you screw up once, it alerts everyone nearby to your presence, and now everyone's shooting at you, and you have to go hide in a bush for two minutes. Somehow, the helicopter still knows where you are, and will continue firing at you, right up until the moment it's technically "lost track of you". Even while ground forces walk around two feet away from you, yelling "we lost him", the helicopter will be delivering barrage after barrage directly at your bush.
And to make things somehow even worse, the helicopter itself does [i]almost no damage[/i]. If you have any kind of shelter at all, it can be completely ignored. Even if you don't, it takes it about twenty seconds of standing completely still in an open field for it to kill you.
It just follows you. Forever. And removes all the fun from the game.
I'm really hoping this fucker goes away soon.