You should probably know that Valve released Portal 2 to download for the users, who pre-ordered the game. However, you cant launch it yet. A friend of mine managed to launch it by modifying 2 files of Portal 2 (dont know which ones exactly). I asked him what engine does the game use, and he answered that it’s probably built on Alien Swarm engine.
So, if this is true, it means that the Portal 2 wont have bunnyhop/abh? Keep your fingers crossed.