Fun Fact: The music for Little Nemo was composed by Junko Tamiya, who also composed the music for the famous game Bionic Commando.
Little Nemo was an adaptation of an adaptation – it was based on an anime called Little Nemo: Adventures in Slumberland, which was based on the American comic strip Little Nemo in Slumberland. This game was another example of how Capcom took their Mega Man side-scrolling formula and successfully applied it to licensed properties.
Nemo is whisked away to the Kingdom of Slumberland, where he has to rescue the king from the Prince of Nightmares. Nemo has to search the levels for the keys required to open the door at the end of every level. Nemo has a bag of candy he can use to feed animals and ride them, thereby gaining their special abilities.
It sounds like a quaint little kid's game, but Little Nemo was quite challenging. Enemies never stopped spawning, and one had to be thorough to find all the keys they needed.