Correcting mistakes in your path
Whenever you accidentally tap on a blue circle to continue but you did not mean to, tap on the sword on the top of your screen, tap the gear located on the top right, tap the character slot, and switch to a different game to play. Once the other game starts, do the same thing to return to your original game and you will resume where you left off.
Never lose a Boss battle for lack of preparation
Switch the game slot after a Boss kills you. When you switch back to your original game slot (where the Boss had killed you), you will have unlimited chances to kill them.