Why does the laser reflect like a semicircle? I was having fun with my laser. What causes this reflection?

Edit: I had an idea and tilted the surface of this plaque by 90°. I now get a straight line, such as the reflection from the plaque below: 

Yes, they're different plaques but THE SAME MATERIAL. The second picture is just a 90 degree rotation of the first! It's as if I turned the first plaque sideways.
Why does the material of the plaque cause the reflection to project a semicircle when tilted? And why is the reflection a line and not a single point, such as when reflected off a mirror?
 A: Your description of rotating by 90 degrees doesn't make any sense. You show an image from one plaque "5th place" then talk about rotating 90 degrees and show an image from another plaque "4th place". It's not clear if this is meant to show the "90 degrees rotated" behavior or just that you see similar behavior for different plaques.
In any case what you are seeing is an example of specular reflection. The surface off which the light reflects is not perfectly flat so you don't get a direct reflection of the beam you send in, rather you get a distorted version. It is like a funhouse mirror.

Notice how the curvature of the surface "stretches" the reflection in various directions depending on the direction of the curvature.
It is possible that the metal plaque off which the light is reflecting was polished (before engraving/labeling) using a circular polisher tool. This polishing might leave a very minimal circular pattern in the surface topography of the metal surface. When the laser beam hits this circular pattern it becomes distorted/stretched in the directions along the curvature of this pattern.
It is a bit difficult to say what exactly is going on without more information.
A: The laser projects onto the plaque which causes a reflection onto the roof. 
On the vertical plane, the laser projects directly into a slit which causes diffraction of the light. This is why the second picture looks like a "stick" of light.
But on the horizontal plane, think backwards. The projection onto the roof comes from the laser hitting it at an angle. For example, think of the point furthest away from the middle. If the laser were to directly shine onto the plaque to reflect on this point ("A"), you'd have to hit the plaque at an angle. 
But that's exactly what the diffraction of the laser through the slit does on the horizontal plane.
