The freighter that Joker is interested in has docked and is receiving cargo. The main entrance hatch has been blocked by a force field, so he would have to find another way to "smuggle" himself aboard. Thus, he would be able to reach the moon of Stroggos and attempt to sabotage their counter-fleet.
The level features a processing facility for captive humans, who are likely intended to be used as sustenance and spare parts.
Quick Level Completion
Differences from Easy to Normal
Differences from Normal to Hard / Hard+
#1: Underneath the ramp leading to the blue forcefield door, there is a hidden Megahealth container.
#2: In the first conveyor belt room, use the belt's added height to jump to the crates and drop down behind there. A suit of Body Armor is stowed away here.
#3: At the very end of the stage, in the narrow corridor under the conveyor belts, destroy the caution-striped wall to your right to find a suit of Combat Armor.