The Commander Keen series was released in 1990 with their first three episodes, the original title released as Shareware. Keen, arming himself with a blaster after exploring Mars and finds himself a pogo stick that he can use to jump high places. Thereafter the series predominately featured Keen's skill with the stick by equipping it by default. The enemies were very cartoony and the game play was solid. The control was absolutely easy and shed no errors in how you needed to control Keen. This game could easily stand up in skill required, fun and graphics with hard hitting classics Nintendo had previously released. Highly recommended if you're an NES platformer fan and are looking for something new to play. Between all the Keen titles you'll find endless hours of fun and replayability.
Plot as described by Wikipedia:
Billy Blaze is an eight-year-old boy genius who has constructed a spaceship in his backyard from old soup cans and other household objects, called The Bean-with-Bacon Megarocket. When his parents are out and the babysitter falls asleep, he dons his brother's Packers helmet and becomes Commander Keen, Defender of Earth. In the first game, Keen is exploring on Mars when aliens steal four spaceship components that he must get back. The aliens are the Vorticons, a fierce dog-humanoid race that had an outpost on Mars. Keen travels through different Martian cities, and eventually recovers all the missing parts. However, when Keen gets back to Earth, he finds the Vorticon mothership looming over the planet, with its cannons ready to attack. In the second game, Keen infiltrates the mothership and has to disable each of the Tantalus Rays targeting different Earth cities. During this adventure, Keen learns that the Vorticons used to be a peaceful race, but were enslaved by the mysterious Grand Intellect. After disabling the cannons, Keen travels to the Vorticon homeplanet, Vorticon VI. In the third game, Keen has to face the Vorticon masses in their cities, all ready to kill Keen. After fighting through many levels of Vorticon-infested cities and military installations, Keen arrives at the lair of the Grand Intellect. There he discovers that the leader of the Vorticons is actually his school rival Mortimer McMire (whose IQ is a single point higher than Keen's). In the final level, Keen has to disable the "Mangling Machine", a large apparatus with many crushing parts controlled by Mortimer. Keen eventually defeats Mortimer and frees the Vorticons. Unbeknownst to Keen, the Mortimer he had defeated was only an android duplicate. The real Mortimer goes on to lead the Shikadi, a race of energy beings who name him the Gannalech. In episodes 4 and 5, he attempts to destroy the galaxy with the Shikadi Omegamatic, but Keen stumbles on a radio message mentioning the Shikadi plans. In the fourth game, he travels to Gnosticus IV, to learn more about the Shikadi from the Oracle. However, when he gets there he discovers that the guardians of the Oracle have been captured by the Shikadi, and are imprisoned in the Shadowlands of the planet. Keen travels through dangerous forests, caves, and islands, and is finally able to rescue all of them. The guardians activate the Oracle, which tells Keen about the Omegamatic being near completion, and reveals the location of the station, in the Korath system. In the fifth episode, Keen travels to Korath III and enters the Omegamatic to destroy its core, the Quantum Explosion Dynamo, and stop the destruction of the galaxy. After avoiding several defense systems, Keen is able to reach and destroy the device. There he learns that Mortimer was the Gannalech, and his intention to destroy the universe is revealed. In the sixth and final episode, Mortimer has Keen's babysitter kidnapped by the Bloogs to distract him. After travelling to Fribbulus Xax, Keen explores the alien planet and saves Molly from being eaten, and also finds out that Molly is Mortimer's sister.