This is making me feel dumb but I can't find that power-up either. At the place where lamarblake and theiza27 had problems.
I have run, climb and ghost eye, as well as the yellow key. I gather I need to find something at the bar upstairs, two screens east of where the red key is. Is this right? If so, does anyone have a hint or two?
Level look cool so far, I'm eager to see where the story goes.
EDIT: I don't feel dumb anymore. I found it and finished the level. I like the concept of being on a huge ship, really cool. And the music was awesome. Some things I didn't like so much:
Why hide all that important stuff behind "invisible" doors? It got tedious after the first one.
Also, I'm not sure I got what was going on. What was that knight doing next to the engine room? Who was that? What happened to the red rebel? This might just be me being stupid, though, sorry if that's the case.
All in all, I enjoyed playing. I was a good level with an unusual setting. Thanks Emeraldfire.