-- in this script, i made a fireball. this is a local script, it will fireserver a script in the serverscriptservice.

Tool.Equipped:Connect(function()
	print "ACTIVATED"
CUA4 = true
Tool.Unequipped:Connect(function()
	print "DEACTIVATED"
CUA4 = false



--–//Services\–
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local UserInputService = game:GetService("UserInputService")

--– Variables----
local player = game.Players.LocalPlayer
local Character = player.Character or player.CharacterAdded:Wait()
local Remote = ReplicatedStorage.Fire.Fireballevent
local Mouse = player:GetMouse()

--–//Settings\–
local Debounce = true
local Key = 'Q'

UserInputService.InputBegan:Connect(function(Input , IsTyping)
	if IsTyping then return end
	local KeyPressed = Input.KeyCode
	if KeyPressed == Enum.KeyCode[Key] and Debounce and CUA4 == true and Character then
		Debounce = false
		Remote:FireServer(Mouse.Hit)
		print "Fireserver"
		wait(.1)
		Debounce = true
	end

end)

-- this is the script in serverscriptservice:

--–//Services\–
local ReplicatedStorage = game:GetService("ReplicatedStorage")

--– Variables----
local Remote = ReplicatedStorage.Fire.Fireballevent

--–//Settings\–
local Damage = 30

Remote.OnServerEvent:Connect(function(plr, Mouse)
	local Character = plr.Character or plr.CharacterAdded:Wait()

	local Part = Instance.new("Part")
	Part.Shape = Enum.PartType.Ball
	Part.Anchored = true
	Part.CanCollide = false
	Part.Transparency = 0.5
	Part.Color = Color3.fromRGB(255,0,0)
	Part.Material = Enum.Material.Neon
	Part.Size = Vector3.new(3,3,3)
	Part.Name = "FireBall"
	Part.CFrame = Character.HumanoidRootPart.CFrame *CFrame.new (0,10,0)
	Part.Parent = workspace

	local tweenService = game:GetService("TweenService")


	local tweeningInformation = TweenInfo.new(

		3,
		Enum.EasingStyle.Linear,
		Enum.EasingDirection.Out,
		0,
		false,
		0
	)

	local partProperties = {
		Size = Vector3.new(10,10,10);
		Transparency = math.random(0,1)
	}


	local Tween = tweenService:Create(Part, tweeningInformation, partProperties)
	Tween:Play()

	wait(3)

	Part.Anchored = false


	local BodyVelocity = Instance.new("BodyVelocity")
	BodyVelocity.MaxForce = Vector3.new(math.huge, math.huge, math.huge)
	BodyVelocity.Velocity = Mouse.lookVector*100
	BodyVelocity.Parent = Part
	local Debounce = true

	Part.Touched:Connect(function(h)

			local tweenService = game:GetService("TweenService")


			local tweeningInformation = TweenInfo.new(

				1,
				Enum.EasingStyle.Linear,
				Enum.EasingDirection.Out,
				0,
				false,
				0
			)

			local partProperties = {
				Size = Vector3.new(50,50,50);
				CFrame = h.Parent.HumanoidRootPart.CFrame;
			    CFrame = h.CFrame;
				Transparency = 1
			}
			BodyVelocity:Destroy()
			Part.Anchored = true
		Part.CFrame = h.Parent.HumanoidRootPart.CFrame

			local Tween = tweenService:Create(Part,tweeningInformation,partProperties)
			Tween:Play()






	end)
end)


That was the fireball script..


In 2020, i also found out how to make things for mobile/pc only. It might be the first thing you think about when making a game, but i'm built different.

if game:GetService("UserInputService").TouchEnabled == true then
	script.Parent.Text = "Device detected: MOBILE"
else
	script.Parent.Text = "Device detected: PC"
end

flickering light using math.random.

while true do
wait(math.random(.1,1))
script.Parent.PointLight.Enabled = false
wait(.1)
script.Parent.PointLight.Enabled = true
end

In this script, i made a cutcene system. I tried to use TweenService and EasyingStyle. At that time i almost always used for i = <number1>,<number2> do, so TweenService was new for me.

--//Variables

local TS = game:GetService("TweenService")
local Camera = game.Workspace.CurrentCamera
wait(1)
player = game.Players.LocalPlayer
button = script.Parent
local debounce = false

--//Scripts

local function CamWithEasyingStyle(StartPart, EndPart, Duration, EasingStyle, EasingDirection)
	Camera.CameraType = Enum.CameraType.Scriptable
	Camera.CFrame = StartPart.CFrame
	local Cutscene = TS:Create(Camera, TweenInfo.new(Duration, EasingStyle, EasingDirection), {CFrame = EndPart.CFrame})
	Cutscene:Play()
	wait(1)
end

local function CamWithoutEasyingStyle (StartPart, EndPart, Duration)
	Camera.CameraType = Enum.CameraType.Scriptable
	Camera.CFrame = StartPart.CFrame
	local Cutscene = TS:Create(Camera, TweenInfo.new(Duration), {CFrame = EndPart.CFrame})
	Cutscene:Play()
	wait(1)
end
local function Cutscene()
	CamWithoutEasyingStyle(game.Workspace.CamA, game.Workspace.CamB, 1)
	wait ()
	CamWithoutEasyingStyle(game.Workspace.CamB, game.Workspace.CamC, 1)
	wait ()
	CamWithoutEasyingStyle(game.Workspace.CamC, game.Workspace.CamD, 1)
	wait() --0.1
	CamWithoutEasyingStyle(game.Workspace.CamD, game.Workspace.CamE, 1)
	wait()
	CamWithoutEasyingStyle(game.Workspace.CamE, game.Workspace.CamF, 1)
	wait()
	CamWithoutEasyingStyle(game.Workspace.CamF, game.Workspace.CamG, 1)
	game.ReplicatedStorage.RemoteEvent:FireServer(player)
	print "fireserver"
	wait()
	CamWithoutEasyingStyle(game.Workspace.CamG, game.Workspace.CamH, .3)


	script.Parent.Parent.TextLabel.Visible = true
	for i = 1,20 do
		wait(.1)
		script.Parent.Parent.TextLabel.BackgroundTransparency = script.Parent.Parent.TextLabel.BackgroundTransparency - .05
	end

	wait(1)
	Camera.CameraType = Enum.CameraType.Custom
	Camera.CameraSubject = game.Players.LocalPlayer.Character:WaitForChild("Humanoid")
	for i = 1,20 do
		wait(.1)
		script.Parent.Parent.TextLabel.BackgroundTransparency = script.Parent.Parent.TextLabel.BackgroundTransparency + .05
	end
	wait(1)
	script.Parent.Parent.TextLabel.Visible = false

end

local Enabled = false
script.Parent.MouseButton1Click:Connect(function()
	wait(2)
	game.ReplicatedStorage.RemoteEvent2:FireServer(player)
	if Enabled == true then return end Enabled = true
	Cutscene()
	Enabled = false
end)