Established in 1987, 3D Realms (legal name Apogee Software) is a developer and publisher, best known for the Duke Nukem series.
Commmander Keen in "The Adventure Begins", episode zero: Printed to Pluto is a Keen 1 mod is being made by (me) szemi.
After saving the universe from Mortimer McMire Keen made his way back to home with his friends. They were flying when Lt. Barker told Keen a blue vortex...
Mort 1: Doomship Dilemma is a Keen 1 mod was originally started by Dr. Villain, but he abandoned the mod, so Szemi has finished it.