Mega Man II

The second handheld installment of the Mega Man series has him (along with his dog, Rush) defeating eight more revived Robot Masters (from Mega Man 2 and Mega Man 3), while finding the whereabouts of Dr. Wily (who has traveled into the future to steal a weapon to counter Mega Man).

Even after his crushing defeat at the hands of Mega Man during the events of Mega Man: Dr. Wily's Revenge, Dr. Wily was already planning his next scheme. If he could get his hands on the time machine (named Time Skimmer in the American manual) that was being developed at the Time-Space Research Laboratory (named Chronos Institute in the American manual), he thought he just might be able to change the past.