it's fun but you have to be careful of cars etc

Interesting. The game sounds like it's hard to master.

In U.S. English, the word sidewalk refers to a paved footpath alongside a street or a road. The sidewalk is usually raised above the level of the road. The curb is a stone or concrete edging between the road and the sidewalk.
In British usage, curb is spelled kerb. What Americans call a sidewalk, British speakers call the pavement.
Merchants that Americans call “street vendors” or “sidewalk vendors” are called “kerb-merchants” or “kerb-vendors” by British speakers.

Never heard of it. What's a 'kurb' anyway?