Mechanics were indeed intuitive and self-explanatory, but it was quite long to win without providing additional challenges. The first time you had to use sheep-eating bushes to reach more sheep was great; the second time, it was a chore, for example. There were perhaps too many sheep / too large a map.
Also, it was unclear whether sheep could re-escape from the final area; there could be some sort of notifier to ensure that. Either the gate clearly has a one-directional arrow, or the sheep would graphically change upon re-entering the containment, etc.