Interesting and different
Right, so I wasn't able to finish the game before writing this because I didn't want to forget and whatever. Speaking of which, it would be nice if there was something to display how far through the game one has progressed, because I have absolutely no idea.
Anyway, as I started playing I was thinking it would be good to have some horizontal control of the player, because if mess up the tempo even the tiniest bit you can't correct it in many cases. Later on though, i realized that it might actually add to the game's individuality, even though there are other games out there with such limitation.
I do not agree with previous comments that hitting the ceiling or running into walls should not kill you, because there would no longer be a point in the game, and hitting your head on a hard ceiling while running is indeed likely to knock you out.
Someone also mentioned they were not able to retain the money they had gained - I do no know if perhaps he is having a separate issue, but it seemed intentional to me that when you die on a level, you do not receive anything from it. In other words, I always got the money when i completed the level, but again, I'm not sure if his/her problem is unique.
Aside from the above, the other thing I really have to say is that the game seems to take a lot of trial and error. It seems virtually impossible to complete a level in one go (although that could just be me), and as I already mentioned, if you mess up the tempo, you are dead.
Parting thoughts (that I forgot to mention earlier), you may want to mention somewhere that if an enemy is stationed under a low hanging area, you should simply attack, and not try to duck as you usually would. I had to find this out from trial and error, and as far as i can tell, attempting to duck and attack at the same time does not work (it has not worked once for me).
Anyway, it's an amusing game, but could use a little work - potentially as little as explaining some of the above in the intro.
Sorry for the long rant, wasn't really in the mindset to write a "short and sweet," but hope some of it was usefull.