Hey StonePaleAle,
Nice game,good work first and foremost :)
Was the game designed for fullscreen cause i have to say you had me squinting. This might have been lessened if the ball was a different colour to the barriers (a bright yellow/orange ball i think would make it easier to keep track of).
Another issue (for me personally - not sure if others will share this) was the controls - I kept wanting to use my right hand! I do play fps's (and tons of games in general, so i am actually use to movement being with the left but for your game, short precise movement is a must - i'd think that most right handed players would feel more at home using the arrow keys for movement (or at least having the option to).
Its actually perfectly designed for those original Atari controllers where you twist the top, i'd love to play it with one of those. :)
The last of the constructive (i hope) feedback is on the boss when you hit the block it should change colour to show the block is weakening.. (haha - if thats what it was doing, i'll admit i didnt get passed it, tried 3 times tho!)
Anyway its getting long and i dont want to end the post with criticism because you did so many things right, i like the block that periodically comes in and bars your progress, gameplay is smooth, graphics are bit small when not fullscreen, but still nice. Ive played a lot of pong style games, paticularly on the Amiga and this one is definately up to par.
Well done.