Instructions need clarification? (Dragon isn't mentioned. Also, separating it into separate Text objects and sentences might help clarify it.) Mention that shooting rainbows at dragons freezes them for a second, for example. Can you kill the dragons? Not sure (but this can be clarified in extended directions.)
Also, instead of having the candy disappear when the unicorn flees (which is surprising and unexpected), what about losing all your candy (in addition to a health point) when you are hit by a dragon or its fire? (It would be like the dragon eating or burning up your candy.)