Re the cancel button, I think moving it elsewhere is advisable, or telling the user that they only have to hit enter to add a new task. Or, adding a mini submit to each new row, but that defeats the purpose of your 'hit enter' function.
I added a "complete mission" button that marks your list as complete, updates stats and rains down confetti.
I made the "cancel mission" button smaller and moved the location as well as adding a "add" button to add items to the list. You can still hit enter to add an item.