I just did the Ravenholm Gravity gun challenge, witch is simple.... only use the gravity gun throughout the whole chapter of "we don't go to ravenholm" AND kill every headhumper and Zombie you see. I must admit it wasn't to bad. gets a little tough when you fight the faster zombies but other than that piece of cake. Let me know what you guys think! And if anybody knows when half life 3 is coming out let me know. The little preview in L4D2 and Portal2 were crazy tantalizing .