Here is a list of all of the commander keen 4-ish mods I could find. I'll make one someday but it won't be all that special, just me messing around.

ATROXIAN REALM [ DOWNLOAD | WIKI ] Atroxian Realm is a major Keen 4 mod released in its completed form on the 16th of January 2016 by Gridlock. This project, in progress for five years, with multiple collaborators from the Commander Keen community, was dubbed "the largest Keen mod that's been made to date" by its author, a claim that no-one has yet disputed. Plays in dos, use DOSBox to load it up, with basic dos commands. If you don't know them, use D-Fend Reloaded. Probably requires commander keen 4.

ALIENS ATE MY BABYSITTER... AGAIN [ DOWNLOAD | WIKI ] Aliens Ate My Babysitter ...Again is a Keen 6 mod, produced by NY00123. It was released on 26 September 2009 and considered as a Mini-MOD. It was originally started as a level pack. The author has modified the original art to have different colors, implemented some graphics from the The Universe Is Toast trilogy, plus added a few patches. Requires Commander Keen 6, Version 1.4... Plays in dos, use DOSBox to load it up, with basic dos commands. If you don't know them, use D-Fend Reloaded.

THE ALPHAMATIC [ DOWNLOAD | WIKI ] The Alphamatic is a Keen 5 mod released on the Fourth of July 2017 by Gridlock. This mod is an Atroxian Realm sequel. The story continues where Atroxian Realm left off. Keen faces a bigger and even deadlier Armageddon Machine as seen in Keen 5. This time he must save the galaxy from VitaCorp and unravel the mystery of the Atroxians. Plays in dos, use DOSBox to load it up, with basic dos commands. If you don't know them, use D-Fend Reloaded. Probably requires commander keen 5.

COMMANDER KEEN'S VALENTINE BASH [ DOWNLOAD | WIKI ] It is the eve of valentine's day and all is not well. Keen's best friend, Johnny Dash has been struck lovesick, another victim of the pernicious holiday! That evening, after an exhausting few hours of work in his backyard clubhouse, Keen receives an ominous message from a mysterious source. The evil Count Chuck has risen once again to afflict the world, and this time Johnny Dash is under his spell. Only Keen stands between earth and the undead hordes. Supplied with magic slingshot and his wits, Keen must do battle with the unholy armies of the Count to save his town, the world, his friend and even... Valentine's day

COMMANDER KEEN x BIO MENACE [ DOWNLOAD | WIKI ] Commander Keen × Bio Menace is a crossover mod between Keen 4 and Bio Menace released by Szemi. It is notable for omitting the world map entirely. Instead of wandering through a specific Map in order to reach and enter an onward level Keen simply flips into the next level after he leaves the current. The High Score level can be reached but only by using the W+F10 cheat.

THE EIGHT ACCUMULATORS [ DOWNLOAD | WIKI ] The Eight Accumulators is a Keen 4 levelpack that explains what happens on Commander Keen's journey home after he saves the Universe from his arch nemesis Mortimer McMire during the mod "Battle of the Brains." The mod was constructed by Bubbatom with a fair bit of help from Ceilick , Mink and Gridlock. Bubbatom began working on the levelpack during mid 2011.

EPISODE 58: THE RUIN OF ROIB [ DOWNLOAD | WIKI ] Episode 58 - The Ruin of Roib is a Keen 4 mod released by Bernie. It features a humor laden plot involving an aged and disillusioned Commander Keen. The mod is set several decades after the conclusion of Keen's childhood adventures and is the first in a series of two, the sequel being Episode 59 - Underworld Ultimate!. (A joke sequel to both, Keen 60: Kreeg Crisis! also exists.) The graphics, patching and level design got highly praised by the community though the high difficulty, especially on hard mode, is often complained about.

EPISODE 59: UNDERWORLD ULTIMATE! [ DOWNLOAD | WIKI ] Episode 59 - Underworld Ultimate! is a Keen 4 mod released by Bernie and is a sequel to his former mod Episode 58 - The Ruin of Roib. Next to its magical theme this mod is especially notable for a very unique game play, which differs from most Galaxy mods. To complete a level Keen has to find and release a balloon. Keen can furthermore produce items by collecting and combining potions. Also Keen will come across point-stealing enemies and destructible walls.

MAROONED ON MARS (EPISODE 1 REMAKE) [ DOWNLOAD | WIKI ] In this episode, aliens from the planet Vorticon VI find out about the eight year-old genius and plan his destruction. While Keen is out exploring the mountains of Mars, the Vorticons steal vital parts of his ship and take them to distant Martian cities! Keen must explore the planet, fight the Martians and their Butler Robots and Tank Robots, find the members of this Vorticon outpost and wrest the parts back from their wicked, clawed hands! The four parts are the Joystick (for manual flight control), the Car Battery (for electrical systems power), the Vacuum Cleaner (reworked as an ion propulsion unit) and the Everclear (alcohol for fuel).

SUBURB SHENANIGANS [ DOWNLOAD | WIKI ] Billy Blaze's home life was like any other eight-year old kid's living in the suburbs. School was a chore and kids gave him a hard time about his outstanding intellect. The only time Billy could escape it all was when he became Commander Keen defender of Earth! Billy had had many adventures in space. He'd saved the Earth, he'd saved the Galaxy and recently he'd saved the Universe. The two lives contrasted each other nicely. Today isn't just another school day though, it's the day of the school's annual IQ test, and to top it off, Billy's lost his bag and missed the bus...

THE TERROR FROM OUTER SPACE [ DOWNLOAD | WIKI ] The Terror from Outer Space is a Keen 4 mod released by Dr. Colossus.