I really wanted to like this game. I guess I do, but it's only "ok" instead of "really good". It started off so well, but quickly went down hill at one annoying boss in particular. Then the mechanics change completely. It starts getting good again after another boss or two and the mechanic change starts making sense, but a good deal of frustration remains.
Why the hell do I have to walk back into boss rooms and re-view the same boss intro every time? I know you know how to do it right because you did for the final boss. Isn't it enough to never give the player any more health and overload one button with 3 different purposes?
That said, most of the boss fights are actually really cool when they aren't being unnecessarily painful.