Hill Climb Racing has more than a touch of Trials to it. You're pottering through hilly levels, trying to get as far as you can before your fuel runs out.
It's less bombastic and complex than Trials, but it's still perfectly playable. It's a more welcoming prospect, with less to go wrong on your runs.
You've got a brake and an accelerator and that's it. The coins you collect can be spent on upgrading your car in order to push further along the course.
And it's perfectly fine, if a little ugly. It acts as a decent entry point to the physics-imbued driving genre, and it's easy enough to pick-up-and-play that anyone can have a bash.