I'm writing a novel which takes place in a carefully built (science-)fictional world. The protagonist is also a fictional creature. Obviously, the reader does not know about the world or the creature's appearance, abilities etc. unless I tell about it. I have refrained from straight up listing stuff - which is highly boring - but instead have set some boundaries, tried to pique the reader's interest with a foreshadowing prologue and I fill in blanks and add to the world as the story goes.
I notice I have a hard time balancing between dialogue and character building, and action scenes. The world and the fictional creatures lend themselves very well for a high paced story with loads of action. However, I'm (also) highly interested in the character development of the protagonist and all the contemplating and thinking that goes with it, slowing down the story significantly. At the moment I have a lot of dialogue, much contemplating (insight in protagonist's thoughts) and short passages of actual action.
I'm afraid that my novel will become boring this way, and that I'm not throwing enough 'bones' to the reader to keep him interested. Are sci-fi stories at all suited for this kind of writing? How do I determine that the mix of above mentioned elements is interesting enough for someone to read, or that the story has indeed become boring? Any guidelines I can follow?
I found this question which already helped me some, but would very much like more input: Striking the balance between dialogue and narrative