Construction Ramp Jumping is exactly what it says: heavy construction vehicles, a ramp, and physics that were never designed for this. You accelerate a road roller or similar down a slope, hit the ramp, and watch twelve tonnes of machinery attempt to fly.
The comedy is in the mass. Ordinary stunt games launch bikes; launching something that weighs as much as a house produces landings that are genuinely spectacular.
Heavy construction machinery — road rollers and similar — which is the joke: they weigh a dozen tonnes and were never meant to leave the ground.
Maximum speed into the ramp, and land on the wheels. Landing on any other part of the vehicle stops the run immediately.
Yes — it runs in the browser with nothing to install.