Cycling Weekly just did an interesting article on cognitive fatigue, and the extend to which combining physical and low-level cognitive training (e.g. decision making, memory tasks etc) can enhance performance.
it strikes me that Zwift and other platforms are missing a trick when it comes to the potential for indoor riding to be gamified. It would be great fun to pursue tasks in virtual worlds while cycling - e.g., collecting tokens from various locations against the clock, putting keys in locks to open shortcuts or prizes, etc.
Obviously it would need to be optional and fully bypassable - I myself am one of those people who finds the trivial gamification of power-ups etc very annoying in training and racing situations and avoids them completely. But if I was offered the opportunity for a fully gamified indoor cycling experience I’d definitely want to try it!
Something like racing with deadly skirmishes. Drop Shop would be about adding weapons and armour. Imagine chasing someone up The Alpe, trying to get close enough to get a good shot while breathing out all orifices. 
Then he does a u-turn and is coming downhill at you all guns blazing. Would be fun!