Commander Keen 4: Secret of the Oracle

Now part of the Goodbye, Galaxy! storyline, Keen ventures into the Shadowlands to rescue the eight members of the Oracle Council — the only ones who can warn of the Shikadi's plan to destroy the galaxy. The Council has been scattered and imprisoned across a vibrant alien world.

Secret of the Oracle (Apogee, 15 December 1991) is the shareware fourth episode and the debut of id's 'Galaxy' engine, with richer graphics, smarter enemies and the iconic pogo-stick platforming Keen is best remembered for.