I got to the end of the medium level (using iPad Pro) and I don’t get the completion option to submit my score no matter how many times I click the treasure chest.

So you reached the treasure chest, but nothing happens when you click on it?

It sounds like you used up all your shovel points to reach the chest. If you don't have at least one shovel point left, the chest cannot be opened. This is normal.

It's not mentioned in the instructions though. Should really be added.

Oh, that must be why. Thank you! Didn't know that.