First things first, it should have The Creeper in it, otherwise it's not The Creeper. Second things second, you need a plot reason for why they are forced into contact with it. After the events of the first RPG, the characters won't be willing to investigate these happenings by choice. So I recommend the same structure as the first one, with the maps, timers, dicerolls and everything, but make an entire new plot and environment.
My idea of the plot was that a harsh Oddworldian winter struck while our little O*-team were travelling to their next assignment, so they were forced to shelter in a dilapidated old base (Think Amundsen–Scott research centre (Look it up!)). As the cold creeps in (Think The Day After Tomorrow), freezing all left outside, the characters are forced to abandon much of their equipment and run deep into the sprawling network of hallways. It's dark, it's cold, and things that look like tentacles are moving behind the air circulation vents...
For zombie fans, bear in mind that The Creeper does secrete dombifying goo. Read
the first one if you don't believe me.
*For Odd
Molluck's Assistant, are you sure I can't convince you to join us? It won't be the same without your cantankerous drill sergeant Slig.