I could imagine Rodland in an adventure-platformer adaptation (2D or 3D) with Tam and Rit hitting their age of puberty. Their adventures could include their maturing and learning to fly with their grownup proportions while having to solve a dire situation they somehow become involved with (along with episodic side-problems, of course).
Their magical skills would be also in development (both of them knowing some simple spells already), and the events surrounding them would force them to learn using said skills in an inventive fashion (e.g. to toss or pull unreachable levers in a way as with the Gravity Gun from Half-Life 2). They would also acquire staffs and other equipment that could provide them other forms of magic (like a cloak of invisibility, or other such things).
And yes, I miss Quake's dark, Lovecraftian atmosphere a lot. Quake II was very disappointing when I first saw its screenshots. "What does this have to do with the original?" I asked.