It looks like the ambulance in the top-left crashed at the same time that you finished the level. This does count as the level failing even though all the people are happy. There is a valid solution to this level.
This might be a little unclear in-game, so we're sorry about that and will look at adjusting it in the future.
For now we've decided not to post solutions since we've recently launched, but here are some tips:
- Use the hint button in the bottom left, there is no penalty for using hints and it can help you find new approaches to levels.
- There are also 3 levels unlocked at any given time, if you go to the menu and then go to level select, you can skip levels you are stuck on and come back to them later.
- Our solution for this level uses 3 arrows on the left side and 1 on the right side.