I made it past by ignoring the damn dropship, and just focusing on shooting the troops and ATACs. That's very counter intuitive because the game dialogue just before tells you to shoot the dropship.Same. There's a drop ship in the distance that shoots a ton at you and there doesn't seem to be anything you can do?
Also you are NOT going to like what comes after that stage, LOL.
Another thing that this game doesn't get enough credit for, is the amazing verticality in the levels.