the problem is that the tolerance on the ray sensor is too small for going up hills
the Cube.001 object has a ray sensor named “onGround” which it uses to see if it is on the ground. Probably a collision sensor should be used instead [but it needs to be sure it is touching the ground, and not a wall…*]
when this sensor doesn’t pulse, you can’t move. This would happen in the air for example [but, you are probably moving in the air already]
increasing the distance of the ray sensor solves the problem
- for a collision sensor to be able to tell when colliding with ground, but not walls, you would need to use different materials for both and have the collision sensor only detect one of them. if this didn’t happen you would be able to do weird things like run and jump up walls, which possibly benefical [for example: ladders] is another behavior, and should probably be implemented with seperate logic bricks. To make it easier to debug where the materials are, give them different material colors [which show up in z key solid mode in the 3d view outside of the game engine], but if you wish to have them the same color in a render or something [like a light map] give them textures [such as inverted None textures with a white color] which override the material color.