Space Pilgrim Academy: Reunion is not called "Year Four" because little of the gameplay takes place in the familiar Academy campus, instead taking place in the city of Aegina and the moon Pan Gu. Personally, I welcomed this change as the new locations offer more exploration and puzzle solving opportunities. The traversal mechanics are much more engaging the earlier running across the Academy system. There are smaller but densely packed locations in the "cities" and a fast travel system to swap between them. Another character from the prequel series returns and sub-plots are resolved. The newly introduced (non-playable) character Calvin provides a fresh perspective of Gail's rebellion from the opposite side of the conflict. Maggie's powers are utilised well as a plot device to develop side-characters.
This brings the Space Pilgrim Academy series to a bittersweet conclusion. The entire series is very interesting and well written. Highly recommended.