Sickengly original concept.
You have officially made the first game I played this year with original use of the keyboard. Definitely great concept for a boxing game.
The art is very well done. I admire how well you used vectors and images without making them clash in a bad way. The animations were smooth and overall its great.
The music, well not much I can say. Its a great choice of music and it sounds good.
As for the gameplay, well if it got me playing for about 30 minutes I think this means it was addicting and had a good replay value. If it wasn't for the different use of the keyboard, rather than those generic controls, I porbably wouldn't have played as long as I did.
I give you an 8 because its not perfect, but it still has a good amount of awesomeness.
Congratulations on making a sucessful game ! :]