Pretty kickass game so far, good mechanics, pretty tight gameplay, and great sprite work!
A mild complaint: when finishing the boss, I think giving the player a solid 6-8 seconds before the stage finishes is good to make sure they can pick up the point item she drops, just for those score-board types.
Also I think for the last stretch towards the boss, it may be fair to put out a rolling barrel with a time bonus item to give players a little more time, I ended up running out in my run against the boss, and I was hitting her consistently but I still lost a life.
At any rate, this is quite promising, and I wish your team well in development!
Happy New Years by the way!