This is the type of game that makes you wish you knew every mechanic right from the start to get an even more satisfying stomping session. As for the story, it was alright I guess, was not that impressed but it did the job. Something that I thought was kind of sad is that the game is just way too short :/
As for the Lunatic difficulty, it is indeed absurdly difficult at the beginning but it just becomes an end turn simulator when your robin starts to have a serious stat advantage over the enemy.