Silly fun, even if a bit too easy.
First off all, I can't knock you for not having a real storyline. Lack of a storyline is what makes madness madness, and as such, this is as genuinely madness as you can possibly get... Storyline, I believe, would have diluted the concept.
I think the recommended mode is far too easy. I went with a tank-like build, maximizing damage output, minimizing damage input, and dumping points into regeneration... Once you do that, there's very little that can kill you, and even with all of the speed-detriments in the game equipped at the same time, you go faster than the fastest enemy in the game. Almost every single upgrade in the game (Except the martial arts, which I simply haven't tried yet) seems wildly overpowered. If you go into a thorn build, enemies will literally walk up to you and kill themself. If you go into a damage-output build, enemies will barely have time to come on screen. If you go into a health + regeneration build, the enemies can't even do enough DPS to kill you even if you weren't fighting back. Considering how effortless the Normal mode was, I can't even imagine how easy the easy mode must be...
**SPOILER ALERT!
Also, you seemed to be building up to this great finale in some sort of badass ending or something, I was expecting to fight some sort of crazy ass, dodging, high hp boss, especially considering you gave us a perk at the very end that gives us 25% crits when on a 1 on 1... only to have a short, cheesy cutscene, kill my guy, and then returning me to the Title screen.. All that work, all that buildup.. for that?!
Your game needs a save feature badly... The first time I played this, I was interrupted and ended up having to press back button on the browser. I came back to the game and looked for a continue button.. to realize its absence. "FUCK THAT" I said and ended up coming back the next day to play it. The game is repetitive and takes a long time to complete, so a save feature would be genuinely useful for this game.
Despite these flaws, this game is a pretty fun stress-reliever. Something to play when you're bored and have an hour to kill but don't feel like actually being challenged.