For the story, yeah It should be continued in the ending. And for the difficulty, no it's not you, all players who played seriously and gived feedback talk about that (even me, I try several before finishing some levels); I wanted each level to be unique and to have it's own Idea of design and how to get over it. For exemple here is the best way to finish the second level:
Thank you for your feedback, it really helps me a lot to improve!