1kb Blackjack
1KB Tetris
1KB Pong
1KB Snake

I've been working on a 1kb Space Invaders game. Its 1060 bytes now, and the enemies can't fire. It has multiple levels of increasing difficulty though.

Anyways:
Code:
//Basic shapes and positions
a = [[-20, 5, 20, 5, 0, -5, 160, 220], [0, 10, 0, 0, 1, -25], [-8, -8, 8, -8, 0, 0, 310, -20], [-5, -5, 5, -5, 5, 5, -5, 5, 40, 180]];
c = _root;
//Enemy x position
x = 1;
//s=Score
//k=Init count
//n=Timer
//y=Enemy y Position
//d=Timer Starting Value
s = k=n=y=d=0;
createTextField("st", -1, 200, 220, 120, 20);
//Enemy Speed
e = 5;
_root.lineTo(320, 0);
_root.onEnterFrame = function() {
	//New Level
	if (k<78) {
		//Draw Prototypes
		//for (k=0; k<78; k++) {
		if (k<4) {
			//b = a[j].split(",");
			b = a[k];
			t = c.createEmptyMovieClip("h"+k, k);
			t.lineStyle(0, 0x000);
			l = b.length-2;
			t.moveTo(b[l-2], b[l-1]);
			for (i=0; i<l; i += 2) {
				t.lineTo(b[i], b[i+1]);
			}
			t._x = b[l];
			t._y = b[l+1];
		} else if (k<27) {
			//Walls
			//for (k=4; k<27; k++) {
			t = h3.duplicateMovieClip("h"+k, k);
			t._x = (k+1)*10;
			if ((k-1)%5 == 0) {
				k++;
			}
			//}         
		} else {
			//Enemies
			//for (k=27, m=1; k<77; k++, m++) {
			t = h2.duplicateMovieClip("h"+k, k);
			t._x = x*25+25;
			t._y = 20+y*15;
			//ens[m-2][m] = t;
			if (x>=10) {
				y++;
				//ens[j] = new Array();
				x = 0;
			}
			x++;
		}
		//}
		k++;
		return;
	}
	//Move Hero                     
	h0._x -= 5*(Key.isDown(37)-Key.isDown(39))*(h0._x-Key.isDown(37)*5>25 && h0._x+Key.isDown(39)*5<295);
	//Fire
	if (Key.isDown(32)) {
		if (h1._y<-20) {
			h1._x = h0._x;
			h1._y = 200;
		}
	}
	//Bullet Check                                 
	e *= z ? -1 : 1;
	if (h1._y>-25) {
		h1._y -= 5;
	}
	for (i=3; i<78; i++) {
		t = c["h"+i];
		if (i>27) {
			if (z) {
				t._x += n>30 ? e : 0;
				t._y += 5;
			}
			if (t._y>200) {
				_root.onEnterFrame = null;
				_root.st = "Game Over";
			}
		}
		if (t.hitTest(h1)) {
			if (i>27) {
				//Hit enemy
				t.removeMovieClip();
				s++;
			} else {
				//Hit Wall
				t._xscale = t._yscale -= 25;
				if (t._xscale == 0) {
					t.removeMovieClip();
				}
			}
			h1._y = -25;
		}
	}
	//End level
	if (s%50 == 0) {
		if (s>0) {
			s += 50;
			d += 4;
			k = 0;
		}
	}
	z = false;
	if (n>30) {
		//Change direction     
		z = _root._width>321;
		d += 2*z;
		n = d;
	}
	n++;
	st.text = "Score: "+s;
};