For any of you who keep getting a glitched out robot part and cannot pick it up, I found the solution (until the creators fix it). All you have to do is make sure the last robot blows up in mid air. Meaning, don't let it charge at you and explode. This can be done by simply shooting the body of the robot (don't hit the red eye, that makes it charge at you). If you do this correctly, once the last robot is killed, the part should just levitate to the ground, and you should be able to pick it up.