Wait for Alexander to open up the portal. Once it opens place Agrippa's head into it.
Revenge Ending
While Alexander is waiting for the portal to open push over the three pillars that are giving it energy.
Super_Secret.rar Password
There is a rar file named "Super_Secret" in the "redist" folder of amnesia that has a password. In order to view the files inside you need a combination of the three endings. Each ending gives you a different part of the password, and when put together you can view the files inside. Below are the pieces you receive from each ending, and the completed password. Revenge ending: lke271 Bad ending: tyr299 Good ending:odn314 Combining them gives you the password of: lke271tyr299odn314