Awesome idea and execution. 7 is a b***h, took me ~20 tries before I had plan for his every attack and managed to kill them.
Amazing variety of weapons and boss battles. One thing that could be improved on is the visibility. Some attacks are hard to see and function description under each platform is nice (I HAVE to see the source code :) ), but could be less distracting if opacity was decreased. This is just a minor nitpick, as if the visuals were better, and some more polish added and balanced, I'd pay for it. Such unique idea!