Cool, polished graphics and nice effects in the game; Only i start feeling bad while for the waving screen effect after 5 minutes: At least it should be stopped while have a battles.
I like the walking sword idea, and I wish i would be some other weapon as well, like an battleaxe or the spear (even a shooting bow). I were missing the power attack to deal higher amount of damage to the boss, while it keeps just rolling on and i'd like to deal to it the "big damages".
I though I would be able to break by sword some of objects in the game, like crates and shelves, for finding something new or/and just for fun; finding even good or bad staff appearing from the boxes. Also the feature in the background story would be great, where player could evolve from just the sword into some kind of ghost warrior with exp. or finding or buying stuff. The spirit would be using the same weapons, but with hands, and the jumping weapon for your level 1 spirit and the visible ghost is a creature level 10.
So here are my toughs but also there should be one rule to be accorded on boss/or even on some normal fights: The how many bullets or how complex is the attack maneuver from enemy, the more player should have time to react to it at the moment: so if there is 3 bullets instead of one bullet, player should have 2 or 3 more time to react it, while this rule shall keep the balance in the game mechanics of on fights.