Corrected entry: The Sovereign Priestess states that the Guardians were hired to kill the monster at the beginning of the film because they "could not risk the lives of their own", but later, it's shown that they pilot all of their ships remotely, thereby not risking any of their own lives.
Corrected entry: Peter Quill uses an old Mattel electronic football game that he has modified to be some sort of tracking/radar device. Where did he get it? When he was abducted, all he has was his Walkman and mix tapes. Not only that, but with access to advanced technology, why would he even need such a device?
Corrected entry: When Baby Groot finds and brings items thinking they are what Yondu wants, he brings a desk that screeches when he drags it. There is no way he could have dragged it any great distance without alerting anyone, including the guards (seen later) posted nearby. Or if he were closer, Yondu or Rocket would have stopped him. Or even put it back (it's not seen again).