my game keeps starting and ending forever?

You forgot to place a wait(1) at the end of the counting loop (for i = 100, 0, -1 do...). Here is the script. Please test to make sure it works and leave a comment when you have any problems.

local RS = game:GetService("ReplicatedStorage")

local SS = game:GetService("ServerStorage")

local Maps = SS:WaitForChild("Maps")

local Status = RS:WaitForChild("Status")

local GameLength = 100

local reward = 50

local money = game.Players.LocalPlayer

-- Game Loop

while true do

    Status.Value = "Waiting for enough players!"

    repeat wait(1) until game.Players.NumPlayers >= 2

    Status.Value = "Waiting for game to start..."

    wait(8)

    local PlayerTable = {}

    for i, player in pairs (game.Players:GetPlayers()) do
        if player then
            table.insert(PlayerTable,player) -- add player into players table
        end
    end

    wait(2)

    local UsableMaps = Maps:GetChildren()

    local ChosenMap = UsableMaps[math.random(1,#UsableMaps)]

    Status.Value = ChosenMap.Name.." has been chosen"

    local MapSpawned = ChosenMap:Clone()
    MapSpawned.Parent = workspace

    local SpawnPoints = MapSpawned:FindFirstChild("SpawnPoints")

    if not SpawnPoints then
        print("Not Found Spawnpoints..")
    end

    local UsableSpawnPoints = SpawnPoints:GetChildren()

    for i, player in pairs (PlayerTable) do

        if player then 
            character = player.Character

            if character then

                character:FindFirstChild("HumanoidRootPart").CFrame = UsableSpawnPoints[1].CFrame + Vector3.new(0,8,0)
                table.remove(UsableSpawnPoints,1)

                local Sword = SS.Sword:Clone()
                Sword.Parent = player.Backpack

                local GameTag = Instance.new("BoolValue")
                GameTag.Name = "GameTag"
                GameTag.Parent = player.Character

            else
                if not player then
                    table.remove(PlayerTable,i)
                end
            end
        end
    end

    Status.Value = "Get ready to Rumble?!!?!"

    wait(2)

    for i = 100,0,-1 do

        for x, player in pairs(PlayerTable) do
            if player then

                local character = player.Character

                if not character then
                    -- left the game
                    table.remove(PlayerTable,x)
                else
                    if character:FindFirstChild("GameTag") then
                        -- They are still alive
                        print(player.Name.."is still in the game!!")
                    else
                        -- they are dead
                        table.remove(PlayerTable,x)
                    end
                end
            else
                table.remove(PlayerTable,x)
                print(player.Name.."has been removed!!")
            end
        end

        Status.Value = "There are "..i.." seconds remaining, and "..#PlayerTable.." players left.."

        if #PlayerTable == 1 then 
            Status.Value = "The winner is "..PlayerTable[1].Name
            PlayerTable[1].leaderstats.Money.Value = PlayerTable[1].leaderstats.Money.Value + reward
            break
        elseif #PlayerTable == 0 then
            Status.Value = "Nobody Won.."       
            break
        elseif i == 0 then
            Status.Value = "Time Up!"
            break   
        end
	    wait(1) -- Moved the wait(1) here.
	end

    print("End of Game!")

    for i, player in pairs (game.Players:GetPlayers()) do
        character = player.Character

        if not character then
            -- ignores them
        else
            if character:FindFirstChild("GameTag") then
                character.GameTag:Destroy()
            end

            if player.Backpack:FindFirstChild("Sword") then
                player.Backpack.Sword:Destroy()
            end

            if player.Backpack:FindFirstChild("Sword") then
            character.Sword:Destroy()
	        end
	    end
	end 

    MapSpawned:Destroy()

    Status.Value = "The game has ended!"
	wait(3)
end