Alright, so after I beat the game, I was enjoying it enough to try the hard mode, and for the most part I found a pretty foolproof strategy that was carrying me through every boss fight, but I got to 7-3, which is the Fujin and Raijin wombo combo boss, and I have to say that it's complete and utter bullshit, and I have absolutely no god damn clue how you're supposed to actually beat it at all. The massive entire board damage plus the unit displacement is absolutely unfair, not to mention once they reach half health they take away two full rows ON TOP OF THE FACT that they spawn absolutely massive amounts of basic mobs, so while you're scrambling to do damage control from all the bullshit they throw at you, a death ball of units is just slowly strolling up the lanes.
Long story short, I don't think I'm going to beat all the hard mode levels. In other news, has anyone actually found what the "mystery on the clothes" things are for all the girls from the yuki onna on? I haven't found anything at all myself.
And in case anyone was curious, I attached a visual guide on what my aforementioned unit layout is. I took an extreme amount of time to make it presentable. Basically the strategy is that you stall out the first and second rounds with the money bunnies behind a wall with a healer (or two, if need be) to heal up the wall in order to get a shitload of cash, then (preferably while the bunnies are slowly killing the units round 2) fill in units backwards from the outside in so the cooldown on them isn't too debilitating, and from then on you have a pretty stacked board going into just about anything. Except the god damn 7-3 duo, apparently.