I love this!
For the full version, I have two suggestions:
*the tutorial should be a prologue, so, perhaps just before you get the task, or, it could do the task bit first, but before the first opponent approaches, there could be a scene where the character flashes back and remembers how to fight. Then after that normal tutorial, the first opponent approaches.
So, it could either be a sort of test by whoever the benefactor is, then you walk towards the thing, or you walk first then do some sort of tutorial fight before the first opponent.
My second suggestion, an endless/survival mode of sorts.
I hope we get to find out what's behind/inside the structure.