Problem: Game would finish level, but would not load next one.
The issue was that all the levels were not included in the build scene, (File -> Build Settings -> Scenes In Build) so even though the level was correct in PlayMaker, it would not load the level in the Game window while testing.
To add scene to build, open the scene up in the editor, then open the Build Settings from File -> Build Settings… or Ctrl+Shift+B and Add Open Scenes
Problem: When changing the shader color on a game object, the color on other game objects changes.
Reason: This happens because the other game objects are using the same Mesh Renderer as the game object your modifying. So when your changing the shader, your actually modifying the Mesh Renderer, not the game object.
Fix: Change the Mesh Renderer for the game object.
In the example picture below, when you change the color on the cube (highlighted red) the color on the capsule changes, because they both are using the same Mesh Renderer (highlighted green). To fix, change either the Cube or Capsule to a different Mesh Renderer (highlighted green)