Comprehensive Game Guide

[Kamikaze28]

I just installed Hero Academy again to take a look at these challenges. As Eijolend said, they are puzzles in the context of a turn, i. e. 'kill the enemy Knight in this situation', where 'this situation' is a predefined positioning of friendly and hostile units.
It's a clever idea to expand an asynchronous strategy game like Hero Academy through familiar problems like this. They give you the opportunity to test teams you haven't bought yet, for example.

But - these challenges heavily rely on the undo function. You are encouraged to try and test different moves to achieve the given goal. I haven't played many challenges, but I presume many only have one valid solution and your challenge lies in finding this one combination of moves through experimentation.
As far as my understanding of OMLs great plan for Outwitters goes, they want it to be a community driven multiplayer game and while it would certainly be possible to add predefined problems like in chess, it just doesn't fit into the greater concept in my opinion. It would also feel very inconsistent to have an undo button in Outwitters.