Cool idea -- I doubt I'll see another game based on rush hour / unblock me in the jam. I like how the idea of wrecking cars introduces a new element to the puzzle scape of destroying cars, but only if you're able to get enough momentum. It's finicky of course, but that's acceptable in a sort of deconstruction of the game.
However, then you reach level 9, where you're boxed in with little movement possible. I'm a believer that a game's strengths and weaknesses show when you up the difficulty, and this level presents very little wiggle room (figuratively and literally) compared to any of the other levels. For me, it ended up playing like a Hell made for parallel parking, as I turned my car just barely enough to allow room for others cars to go past. I ended up never managing to wreck the car on that level and instead sneaking around the edge, to discover a new mechanic waiting for me in the final levels (ice cars, which are cool but the puzzles don't seem made to take full advantage of their unique property).
Anyway, if you could find a way to reduce the finick, this is pretty cool.