Commander Keen Episode Four: Secret of the Oracle is the second of the two episodes in Goodbye Galaxy! series.
In Episode Five, after getting information from the Oracle, Keen lands on a massive Shikadi space station, the Omegamatic, nicknamed the Armageddon Machine.
Keen need to seek out the mysterious Grand Intellect. The gameplay centers on Keen advancing through the Omegamatic to deactivate it.
Even through still using the same engine, the graphics in Episode Five is the best among all episodes.
You can download Commander Keen Episode Five: The Armageddon Machine here.