Every car in the lot is boxed in by another one, and all of them want to leave. Parking Jam gives you a fresh lot each level and asks you to empty it without causing a pile-up. Later lots hold more cars and add obstacles, so the layouts get noticeably harder.
The whole puzzle is about order. A blocked car can only get out once the vehicles in its way have moved, so you need to spot which one should go first, which car that frees up, and so on down the chain. Moving the wrong car at the wrong moment simply creates a new jam. A good habit is to find the cars that already have an open route and start with them. Number puzzles such as 2048 Classic reward the same habit of thinking a few moves ahead.
