Why does my Roblox game delete all parts when testing?

I'm working on a Roblox game, but whenever I test it, none of the parts I added in the game display in the Explorer or in the game itself. It works perfectly fine when I view it in the studio, though. Here is the only script that I have running in game:

local cam = workspace.CurrentCamera
cam.CameraType = Enum.CameraType.Scriptable
wait(0.1)
cam.CameraType = Enum.CameraType.Scriptable
cam.CFrame = CFrame.new(Vector3.new(-122.911, 43.925, -46.551))
--cam.CFrame.Rotation = CFrame.new(Vector3.new(-31.43, -174.653, 0))

Any help is appreciated!