Ballmen for Half Life 2 Ballmen Mod – a Half Life 2 mod where you can walk on walls and do all sorts of insane jumping due to weird gravity. Please tell me someone is making a Möbius strip map for this mod. I’d always wanted to make one of those for Quake 2. Share this with your friends:TwitterRedditTumblrFacebook By Adam Keys Telling a joke. Typing. View all of Adam Keys's posts.