I played Riddle School 1-5 and loved them. I honestly felt like you ended the series perfectly and didn't expect you to make a...well a spiritual "6th".
This one improves on the series, an already difficult thing to do, while still keeping the base set by the series. I for one love the direction you've taken and will patiently await further entires. Oh and in case it wasn't obvious, it's a 10 from me.