the game looks very beautiful and quite polished! like frogger but eco-aware :D
i agree with the comments that once you find the right strategy (spamming cars through a single line) it becomes fairly easy to stop the evil froggos. maybe a change of pattern would work here!
or maybe have some more levels with a pause in-between to give some rest to your hand (after it clicked so frantically!)
all in all, such a nice entry :)