Good game
I do like how you model Hilda looking like a real anime character
I don't know what to rate this because the gameplay is just Hilda guessing your number like the tittle say it all
I think you should change the character to something else like just a regular anime person because, I thought that when the character is a witch I imagine she would do something like powers and staff but, in the gameplay that didn't happen, and not defining that she's a witch.
I think you should add some Easter eggs like choosing the number 69 and she would reply "oh yes the funny numbers" or something like that
So I think I'll rate as 4/5
Edit: Also why you put the Genre as Puzzle I don't think that this game is a puzzle at all or at least in my opinion