Script works in 'Run' but not 'Play Solo'? [ANSWERED]

The problem is that Torso, and Humanoid has not loaded yet, so when the script fired, it did not find Torso or Humanoid, I have remade your script with some-what explanations, you could simply use the WaitForChild method [Which I did not use but should've :P], and that would've waited until the Torso and Humanoid have loaded;

function WaitForChild(str,obj) --I have created a new function for you; this will help to wait for the Child; not necesary, could've simply used 'str:WaitForChild(obj)', but eh :P
repeat wait() until str:FindFirstChild(obj) --This will repeat until the code finds 'obj' within 'str'
return str:FindFirstChild(obj) --This will return 'obj' when it is found
end --This ends the code block for the function

local Figure = script.Parent.Parent --Figure is the Script's Parent's Parent
local Torso = WaitForChild(Figure,"Torso") --This will repeat until 'Torso' is existant within 'Figure', and will return it
local LeftArm = WaitForChild(Figure,"Left Arm") --This will repeat until 'Left Arm' is existant within 'Figure', and will return it
local RightArm = WaitForChild(Figure,"Right Arm") --This will repeat until 'Right Arm' is existant within 'Figure', and will return it
local LeftLeg = WaitForChild(Figure,"Left Leg") --This will repeat until 'Left Leg' is existant within 'Figure', and will return it
local RightLeg = WaitForChild(Figure,"Right Leg") --This will repeat until 'Right Leg' is existant within 'Figure', and will return it
local Humanoid = WaitForChild(Figure,"Humanoid") --This will repeat until 'Humanoid' is existant within 'Figure', and will return it
WaitForChild(script.Parent,"Roar") --This will repeat until 'Roar' is existant within the Script's Parent
WaitForChild(Figure,"Monster") --This will repeat until 'Monster' is existant within 'Figure'
WaitForChild(game.Workspace,"Crumble") --This will repeat until 'Crumble' is existant within 'game.Workspace'
WaitForChild(Torso,"Fire") --This will repeat until 'Fire' is existant within 'Torso'
WaitForChild(Torso,"Smoke") --This will repeat until 'Smoke' is existant within 'Torso'

Humanoid.Died:connect(function() --This will fire when the Humanoid dies
Torso.BrickColor = BrickColor.new("Really black") --This will turn 'Torso''s BrickColor to 'Really black'
LeftArm.BrickColor = BrickColor.new("Really black") --So on
LeftLeg.BrickColor = BrickColor.new("Really black") --So on
RightArm.BrickColor = BrickColor.new("Really black") --So on
RightLeg.BrickColor = BrickColor.new("Really black") --And so on
Figure.Monster:Destroy() --This will destroy 'Monster' within 'Figure'
script.Parent.Roar:Play() --This will play the 'Sound' 'Roar'
wait(1.5) --Will wait '1.5' seconds [One and a half]
game.Workspace.Crumble:Play() --Will play the 'Sound' 'Crumble'
Torso.Fire.Enabled = false --This will disable the 'Fire' type instance within 'Torso'
Torso.Smoke.Enabled = true --This will enable the 'Smoke' type instance within 'Torso'
wait(4) --Will wait '4' seconds
Torso.Smoke.Enabled = false --This will disable the 'Smoke' type instance within 'Torso'
end) --This ends the code block for the Function/Event

Hope this helped!