First round was a 20 minute phone interview with HR and then the second round was a 2 hour interview panel at the office. It took about a week and a half to hear back after my final interview

After 3 rounds of interviews, numerous "offer is still pending for approval" and "will update the offer next week", HR just fell off the face of the earth!  Keeping me hanging through long stretches of time between communications and updates then failing to deliver on the promised status updates showed a lack of basic professional courtesy. If you have time to respond to feedback, surely you have time for a quick update.