Will be a cool game?
The background story could be a little longer, like 1-2 frames plus. I'm kinda glad you included an escape ending, but I could get out even if didn't search all over the place. Make us search, and talk to a prisoner maybe, get him/her out as well, make it so we cannot escape until we do a final thing, all of the other things leading to that one. (Ok, I guess you've already thought about that) You've made a good framework, now fill it! (PLZ?)
I liked the text boxes, and the navigation, simple and easily clickable. 3/5, but please finish it, don't let the effort fly away. No need to animate stuff this much, just make them interactive. After that animate if you'd like. (Those hanging chains r mad though :-))
Peace