This mod comes with a small map and 10 scenarios, you must access them from the scenarios or gameplay selector menu.
The map
A heightmap based hill for use of perpetually tumbling objects.
The scenarios task you with climbing the road and surviving the infinite stream of objects. Whether it be rocks or cars or boxes, you will be challenged.
The Vehicle selector for scenarios is a little broken and now unsupported, but it does still work, just looks very odd.
This is an old video
https://www.youtube.com/watch?v=TSR7vMvVnDY
You may need to reload the level sometimes as the physics go mad when you reset the scenarios sometimes.