I happen to agree with everyone else. The game was fun but there is many problems I find with it [and when I say fun, it was only fun for about 4 minutes. Around that time I realized that I was never going to die]. I definitely agree that you are way too over powered. That coupled with the fact that upgrades are too inexpensive. I didn't play the game long enough to see if that was due to game length but with every upgrade I became more and more unstoppable thus not presenting a challenge thus not giving me a reason to continue playing.
The weapons are something that kind of drives me nuts. Ninjas had a ridiculous array of weapons. The thing is though, most of them derived from farm tools because ninjas were peasant folk who lived in small, poor, overtaxed villages. The Diamyo's men [Samurai] were who used katanas and yumi bows. Not that a ninja would be incapable of wielding a katana [the yumi bow is a different story as that weapon takes years of practice to be efficient with which ninjas just didn't have yumi bows at their ready availability] but their fighting style [ninjutsu] required more stabbing weapons than slashing weapons due to Samurai armor being resistant to slashing and blunt weapons due to the devastating kanabo. Although the kusarigama is a cool weapon, it is not at all even comparable to the katana because that weapon was literally made from farmers scythes with a steel ball on the end attached by a chain... The weapon was easily breakable by the craftsmanship of the katana. Katanas have been called the 7 year blade because that's the least amount of time required to make one with any sort of quality. Read about the creation of the katana and you would realize that that weapon should easily be at the top of the list right next to the yumi bow which I am not going to get into because I just went on a 5OO word rant [probably more] on why I don't think the katana should be the second weapon on the list.