local plr = game.Players.LocalPlayer
local char = plr.Character or plr.CharacterAdded:Wait()
local hum = char:WaitForChild("Humanoid")
local hrp = char:WaitForChild("HumanoidRootPart")

local baseSpeed = 16 -- standard roblox speed
local jumpBoost = 5 -- how much faster per hop
local speedCap = 100 -- dont go too crazy
local decelRate = 50 -- slow down speed when sliding
local lowFriction = 0.01 -- makes it slippery
local currSpeed = baseSpeed

-- save original props
local origProps = hrp.CustomPhysicalProperties or PhysicalProperties.new(0.7, 0.3, 0.5, 1, 1)
local slipProps = PhysicalProperties.new(origProps.Density, lowFriction, origProps.Elasticity, 100, origProps.ElasticityWeight)

local lastHzSpeed = 0
local lastDir = Vector3.new(0, 0, 0)
local sliding = false

-- jump to boost speed
hum.Jumping:Connect(function()
    currSpeed = math.min(currSpeed + jumpBoost, speedCap)
    hum.WalkSpeed = currSpeed
    sliding = false
    hrp.CustomPhysicalProperties = origProps
end)

-- heartbeat for updates
game:GetService("RunService").Heartbeat:Connect(function(delta)
    if hum.MoveDirection.Magnitude > 0 then
        lastDir = hum.MoveDirection.Unit
        sliding = false
        hrp.CustomPhysicalProperties = origProps
    end

    local hzSpeedNow = (hrp.Velocity * Vector3.new(1, 0, 1)).Magnitude

    if hzSpeedNow < lastHzSpeed * 0.5 and lastHzSpeed > baseSpeed * 1.5 then
        currSpeed = baseSpeed
        hum.WalkSpeed = baseSpeed
        sliding = false
        hrp.CustomPhysicalProperties = origProps
    end

    lastHzSpeed = hzSpeedNow

    if hum.MoveDirection.Magnitude == 0 and currSpeed > baseSpeed then
        if not sliding then
            sliding = true
            hrp.CustomPhysicalProperties = slipProps
            hrp.Velocity = Vector3.new(lastDir.X * currSpeed, hrp.Velocity.Y, lastDir.Z * currSpeed)
        end

        currSpeed = math.max(baseSpeed, currSpeed - decelRate * delta)
        hum.WalkSpeed = currSpeed

        local velHz = hrp.Velocity * Vector3.new(1, 0, 1)
        if velHz.Magnitude > baseSpeed then
            hrp.Velocity = Vector3.new(
                lastDir.X * currSpeed,
                hrp.Velocity.Y,
                lastDir.Z * currSpeed
            )
        else
            sliding = false
            hrp.CustomPhysicalProperties = origProps
            hum.WalkSpeed = baseSpeed
            currSpeed = baseSpeed
        end
    elseif hum.MoveDirection.Magnitude == 0 then
        currSpeed = baseSpeed
        hum.WalkSpeed = baseSpeed
        sliding = false
        hrp.CustomPhysicalProperties = origProps
    else
        hum.WalkSpeed = currSpeed
    end
end)