I really like this game, had a lot of fun with it! You need quick reactions but it doesn't feel unfair - if I failed I knew it was my fault. I spent quite a while trying to beat my highscore :)
As others have mentioned it would be nice to have the cars spawn off screen, and I also found that if you died while a cloud was in the middle of the screen it would cover the 'game over' text (very minor but something to keep in mind).
Really solid entry, simple but fun - nice one!