The second part, where the immigration worker in Intramuros asks you to put 2000p in your passport is illegal, and a legitimate complaint. I don't know why you didn't realize it at the time, as it's obvious that all payments are made at the cashier window. You should have refused.

Exit clearances have been a standard procedure in the Philippines for a long time, and there are signs and documentation everywhere, including in your own passport. If you have stayed more than 6 months, you need to apply for an exit clearance at any immigration office at least a week in advance of your departure. The Intramuros immigration officer was under no obligation to issue you an exit clearance that same day. However, in my experience, they are usually issued on the same day in the satellite offices. The main office in Intramuros tends to be slower because of the larger number of people they serve.

The airport immigration officers were just doing their job when they blocked your departure. That was YOUR fault for not paying attention to visa procedures. You don't have any foundation for a legitimate complaint there.

The Intramuros immigration officer is probably not regularly corrupt. His thinking was probably along the lines of "If I make an extra effort to help you out and rush this through, then you can also help me out with a tip." He was doing you a favor by giving your needs priority over others so he expected compensation. Yes that IS corruption, illegal, and he should not have done it. But I doubt that he waits in anticipation every day to take advantage of people. You probably would not accept that it can't be processed in one day, and you pushed him, so he agreed to do it with compensation. Both of you made stupid mistakes.