Re:hmmm (Score 2)

Get a tread mill that can detect the amount of pressure being placed on it and in how many spots. If it finds 2 spots (2 feet) then the user is most likley standing still. If only 1 foot than you know the person is walking. You can use time to determine the person's stride. I'm not sure about climbing, but you could still do jumping as long as you told the user to just jump straight up. When the treadmill detects 0 pressure being placed on it have it go into jump mode. At the last time it detected have it store the horizontal velocity and use this as the velocity while no pressure is placed on the pad. As for the height of the jump, i'm not really sure since you would have to know how the long the jump would be overall. For arbituary direction maybe you can have the user wear a certain type of shoe so that the sensors on the treadmill can determine which direction the user is facing and adjust within the game.