I think that's what's good about these quick type of games is that if you lose, you can quickly pick it up again and learn from your mistakes. As long as the player has some resolve and time, they'll hopefully solve it!
I think finding the right balance can be tough because the developer knows what to look for, and knows the timing of everything, while a newcomer is completely fresh. My game started off far to difficult when I first had people test it, but now I'm thinking I made it a bit too easy. An endless struggle!