1)I think more difficult-to-navigate environments would make the game more challenging. Mazes or obstacles that would seem passable at first but are actually not, forcing you to think of other strategic routes could be something cool to implement.
2) I think it would actually be very silly if you had the option of either eating some flies or bringing them all home to the frog mom. You could choose to be cheeky on purpose or actually fulfill the original request which could create multiple different endings. More of your choices could have silly consequences.