What can I say? A great idea unfortunately ruined by partially not necessarily good execution. The music is nice, the graphics of the background is great, as well as its animations, but... and here are the "buts":
1. Those Chinese or Japanese symbols during the fight are highly disturbing. You are preparing an attack or trying to evade and then - symbol pause - and after that you get attacked. Change it so there would be some kind of a mark in the corner saying that the rage mode is active etc.
2. Another irritating thing: during the fight the enemies are leaving the screen and even you can kick them out of it, making it completely impossible to know whether the enemy is dead, where he is... lock the borders during the rounds of the fight.
3. The attacks that you are buying are suposed to be unblockable, but in fact they are not. Many times the enemies were blocking my special attacks or even attacking me at the same time.
4. Every single time you enter the new chapter or go back from the shop screen you have to click the screen, because the game loses focus.
5. As it was already mentioned below, it can happen that after the regular fight or a boss fight you will get stucked with nothing to do. No mission end screen, no more enemies and no way to die. The only thing to do is restart the game, but with losing ALL of your progress, including upgrades. It happened to me after beating one of the bosses, causing a LOT or rage. Thus => 6...
6. Make tha game save progress after each finished round, so people won't get irritated because of that issue. Also consider that some of the people may not have enough time to finish the game in one playthrough because they are working, studying, learning... and the levels are long and by that I mean the space you need to pass.
7. Many times Billy was starting to run despite I did not press the directional key in the way to make him do it.
8. About running: that "breaking" may be a nice animation, but it's a bit ridiculous, come on, who stops running like this? ;-)
Whoa, that were lots of points :-) But I must say that in general I like the game, but it needs a lot of improvements. The controls are easy to learn and even master, you also need to plan a good strategy in some fights against inconvenient opponents. I would even like to play an extended version with more stages, enemies, maybe upgrade scheme. There is lots of potential in this idea, go for it! :-)