The classic arcade game I was referring to yesterday was Breakout (imaginary cookie goes to Sir Sapo for guessing right). The BlockKing will be bouncing around the arena like a breakout ball. Every time he hits the floor, he breaks a little bit off of it. Therefore, you must be able to beat this boss before he completely destroys the floor, dropping you to your doom.
I said Breakout, but this boss is really inspired by a boss in a Sonic game. I thought it was a really great idea, and just had to use it.
I plan to upload a new demo tomorrow, in case anyone wants to try out the game with the ammo restriction.
That sounds like a cool boss, I hope you can get it to work like you want it to, because that would be kickass!