Your friend very much did give me trouble.
Great game! It took me a couple of tries to get all the riddles, but I got there in the end.
Some small issue: when you enter a wrong answer, the textbox loses focus, which can be a bit annoying. Also, some of the pages are barely visible, making them difficult to find. It might be helpful to add a sound cue or some other feedback when you get a riddle correct.
Great game overall!