Interesting...
...but not for long. As a matter of fact, I actually started looking foward to the next boss battle, because they meant a new combatant to be defeated in a new way. This "typekill hordes of ninjas" system just got a bit old.
Sadly, I was forced to quit in the 5th boss battle after I failed to realise how to beat those wizard ninja clones for the third time. Try making the hints a bit less subtle because I really don't get what you're saking if you got a black bar running back and forth under three different buttons. Attempt to push one of those while the black bar was under it resulted in failure.
Additionally, I found a strange bug, where a ninja with NO HEALTH LEFT continued to run and threw a flashbang at me. HEre's a screenshot - remove the space : img223.image venue.com/img.php?image=26238_Ninja_1 22_562lo.jpg
On the bright side, the game shines with graphics and audio ( though I wouldn't have minded a few different death sounds for the mounted ninjas) plus, as mentioned beofre, the boss battles brought in a nice change from constant typing.