You made this solo? Wow! The amount of efforts that went into this - with the world building, and multiple character designs...good job! Even though the challenges seemed a little too easy, it does make sense in the context of it being an educational game. In a way, it was good the gameplay was so forgiving. It was like some good revision for me.
Also, the way our choices reflected in the earth becoming prosperous and greener - that was a satisfying touch too! Also that mischievous owl part - made me smile!
I do have a suggestion though. While I can see you have made a tremendous effort to match your 3d model characters with the background image; there was still some amount of disconnect. If it's possible for you to animate the background ever-so slightly (Small touches, like trees swaying in the wind, something minimal to indicate the water as flowing; I'm talking about something as small as a 1 second animation on loop) , it can possibly go a long way! (in case this helps you in some way)
Well done!