Add a scheme option that when you are walking on the edge of a cliff, the worm instantly stops when it reaches the very limit of the land. To fall from the cliff, you would need to press the arrow again to confirm you really want to fall.
This will avoid simple mistakes such as falling, ergo it will save turn time of players, since they will not need to spend several seconds, walking subpixel per subpixel many times to ensure they reached the limit without falling (for precise jumps, overhang shotgun trick, cow against wall, etc). This would also avoid ruining the whole strategy, the whole fun while spectating a competitive play. Yes, because even pro players fall without intention and this is not good to watch on a stream. It might be funny, but in terms of pro play, this is not cool.
It would also help newbies, since they would fall less times and the learning curve would be smaller.