The third boss or the Heli-Chopper is quite simple.
Video GuideText Guide:
1. Proceed down, jump over the samurai with the sword, smoke roll (RT) through the missile man and jump down, heading to the left.
2. The chopper will then start a barrage of small arms fire, simply smoke roll through it once as it heads to the right, and again as it comes back the other way.
3. Next are grenade barrages, as the chopper drops the first line of grenades and the second are on their way down, smoke roll (RT), to the left and you should faze back in just after the first grenades have exploded, as the chopper comes back to the left the second time, do the same smoke roll, just to the right, may take a bit of practice.
4. Next are cluster missiles, as the helicopter flies by, he will drop off a big silver missile which will explode in midair sending out a whole barrage of yellow pebbles. For the first wave (as the chopper heads right), keep your character flush up against the white wall on the far right, and they will miss completely. As the chopper makes its pass back to the left, it will do the same attack, only this time, smoke roll (RT) through the pebbles.
5. This time the chopper will be on ground level flying slowly to the right shooting regular heat seeking missiles, simply dodge two of the missiles and cause them to hit the white wall behind you collapsing it. Quickly jump through, grab the blue suit, and sprint run (HOLD RT) through the cavern to evade the missiles/chopper.
6. As you approach the end of the cave, you'll see a small platform hold the green suit (Green star), grab it and quickly jump up and to the right, and then double jump back to the left so that you're up against the cliffside, now shimmy (jump) your way up the cliffside, rubbing the blocks above you till they crumble.
7. Keep climbing, being aware of the chopper thats about to fly up the end of the cliff and jump into the corridor at the end, run to the left and grab the black suit again and look right.
8. As the chopper flies directly to the left into the corridor smoke roll (RT) right so that you pass through the chopper, which will cause it to crash into the wall and ensue the ending.