Rising Lava

Lesson 10 of 18 in Coddy's Roblox Game: Endless Tower course.

Waiting at the bottom should not be safe. A sheet of lava starts under the tower and, after a short delay, rises steadily until it is 2 studs under the top, so everyone has to keep climbing.

A tween can wait before it starts: the sixth argument of TweenInfo.new is a delay in seconds. For a steady climb, the tween's time is the distance over the speed:

local seconds = top / Settings.LavaSpeed
local info = TweenInfo.new(seconds, Enum.EasingStyle.Linear, Enum.EasingDirection.InOut, 0, false, Settings.LavaDelay)

The lava is not solid (CanCollide false) so nobody can stand on it, and its Touched uses killOnTouch, the same function as the kill bricks. It starts at a height of -2 and rises to top - 2, exactly top studs.

Challenge

Medium

Near the top: local lava = nil. Make buildTower return top.
Write startLava(top): make an anchored Part named Lava, not CanCollide, 30 by 2 by 30, at Vector3.new(0, -2, 0), orange Neon (Color3.fromRGB(255, 90, 20)), in the workspace, with Touched connected to killOnTouch. Tween its Position to Vector3.new(0, top - 2, 0) over top / Settings.LavaSpeed seconds, Linear, after a delay of Settings.LavaDelay.
At the end: local top = buildTower() then startLava(top).

This lesson's lava is fast so the Check is quick. Press Play, then Check.

Try it yourself

local Players = game:GetService("Players")
local ServerStorage = game:GetService("ServerStorage")
local CollectionService = game:GetService("CollectionService")
local RunService = game:GetService("RunService")
local TweenService = game:GetService("TweenService")
local Settings = require(game.ReplicatedStorage.Settings)

local stages = ServerStorage.Stages
local tower = nil

print("Each tower has " .. Settings.StageCount .. " stages")

-- Every player gets Wins on the leaderboard
Players.PlayerAdded:Connect(function(player)
	local leaderstats = Instance.new("Folder")
	leaderstats.Name = "leaderstats"
	leaderstats.Parent = player

	local wins = Instance.new("IntValue")
	wins.Name = "Wins"
	wins.Parent = leaderstats
end)

-- Anything tagged Kill ends a life
local function killOnTouch(hit)
	local humanoid = hit.Parent:FindFirstChild("Humanoid")
	if humanoid then
		humanoid.Health = 0
	end
end

-- A vanishing step fades soon after someone lands on it, then comes back
local function makeVanish(part)
	part.Touched:Connect(function(hit)
		if part:GetAttribute("Gone") or not hit.Parent:FindFirstChild("Humanoid") then
			return
		end
		part:SetAttribute("Gone", true)
		task.wait(Settings.VanishDelay)
		part.Transparency = 0.8
		part.CanCollide = false
		task.wait(Settings.VanishTime)
		part.Transparency = 0
		part.CanCollide = true
		part:SetAttribute("Gone", nil)
	end)
end

-- A laser slides to its Slide offset and back, forever
local function makeSlide(part)
	local info = TweenInfo.new(Settings.SlideTime, Enum.EasingStyle.Linear, Enum.EasingDirection.InOut, -1, true)
	local goal = { Position = part.Position + part:GetAttribute("Slide") }
	TweenService:Create(part, info, goal):Play()
end

-- A bounce pad throws whoever lands on it up into the air
local function bounce(hit)
	local root = hit.Parent:FindFirstChild("HumanoidRootPart")
	if root then
		root.AssemblyLinearVelocity = Vector3.new(0, Settings.BouncePower, 0)
	end
end

-- Spinners turn a little every frame
RunService.Heartbeat:Connect(function(dt)
	for _, spinner in CollectionService:GetTagged("Spinner") do
		if spinner:IsDescendantOf(workspace) then
			spinner:PivotTo(spinner:GetPivot() * CFrame.Angles(0, math.rad(Settings.SpinSpeed) * dt, 0))
		end
	end
end)

-- Turn on every obstacle in a stage, by its tags
local function setupStage(stage)
	for _, part in stage:GetDescendants() do
		if part:HasTag("Kill") then
			part.Touched:Connect(killOnTouch)
		end
		if part:HasTag("Vanish") then
			makeVanish(part)
		end
		if part:HasTag("Conveyor") then
			part.AssemblyLinearVelocity = part.CFrame.LookVector * Settings.BeltSpeed
		end
		if part:HasTag("Slider") then
			makeSlide(part)
		end
		if part:HasTag("Bounce") then
			part.Touched:Connect(bounce)
		end
	end
end

-- Any stage, at random
local function pickStage()
	local all = stages:GetChildren()
	return all[math.random(1, #all)]
end

-- Put a copy of a model on top of the tower; returns the copy and the new top
local function stack(template, bottom)
	local copy = template:Clone()
	local box, size = copy:GetBoundingBox()
	local lift = bottom - (box.Position.Y - size.Y / 2)
	copy:PivotTo(copy:GetPivot() + Vector3.new(0, lift, 0))
	copy.Parent = tower
	return copy, bottom + size.Y
end

-- Build a new random tower, bottom up
local function buildTower()
	tower = Instance.new("Model")
	tower.Name = "Tower"
	tower.Parent = workspace
	local top = 0
	for i = 1, Settings.StageCount do
		local stage, newTop = stack(pickStage(), top)
		top = newTop
		setupStage(stage)
	end
	stack(ServerStorage.Finish, top)
end

buildTower()