Greetings Apple users, let an android user show you how to do it.lol, jk. To destroy the Driller, it will take you many attempts but it can be done. Running backwards hit jump roll, with your gun aimed high position , fire. Immediately turn and find a straight path. Hit jump and roll forward 3 * in a straight plane. Yes the rocks will be in your way so guide accordingly. Immediately turn to the right 180 aim high, shoot. The closer you are to being directly below in view of Target the better your chance. Running forward again jump roll 3 or 4 more times quickly turn and fire. The fourth will be the Most difficult simply due to time. Running forward jumping and Rolling as many times as it takes to get to the 4th target, go to the left side, quickly turn right firing up. The doors will come down on the driller and stop it. If you make any mistakes in the first targets and I mean any, let yourself get killed because you have to do it perfectly to make it to the end. If an old man can, do it..........
As for the large robot you need to simply go to the opposite side of the crane and hide behind out of his missile view. Once he fires the third missile, pop your head out and take out the green bulls eye. Keep repeating that until his energy is depleted. After killing him look up at the crane, locate the ladder and shoot it.
If you like this game you'll like Nova 3 better. I had to quit playing Mass Effect infiltrator because at the second ogre mech , the game kept crashing.