Interesting premise, but extremely rushed due to its restricted timeframe. Had this been an entire series rather than a short movie, it likely would've been properly paced. As for the genre, I am certainly in favor of mixing the medieval-ish aspects with those of the Second World War. The animation was good, sounds were good, characters were meh (due to poor pacing, although with some extension of the series, this would have been resolved. (Like there was very little emphasis on any of the characters)).
Could be better with an expansion on the story, but considering that it's 8 years old, there likely won't be any.