After spending an hour cloning your game to see if was able to make it under 1k, I ended up with a .jar file of about 3.5kb, with a bit more of compression I think I can make it 3kb. Then I realized I could actually download your code. I only have one thing to say, what the hell dude? Are you the God of Compression?
Here is the code BTW,
import java.awt.Canvas;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JFrame;
public class A extends Canvas implements Runnable {
byte[]bb={1,0,0,0,1,1,0,0,0,1,1,0,0,0,1,1,0,0,0,1,1,0,0,0,1};byte[]sh={1,0,0,0,1,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,1,0,0,0,1};byte[]as={1,0,0,0,1,1,0,0,0,1,0,1,0,1,0,0,1,0,1,0,0,0,1,0,0};byte[]fo={1,1,1,1,1,0,0,1,1,0,0,1,1,0,0,1,1,1,1,1,0,0,1,0,0,1,1,0,0,0,1,0,0,0,1,0,0,1,1,1,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,0,1,1,1,1,0,1,1,1,0,0,0,1,0,0,1,0,0,0,0,1,0,1,1,1,1,0,0,1,1,0,0,1,1,1,1,1,0,0,0,1,0,0,0,1,1,1,1,1,1,0,0,0,1,1,1,0,0,0,0,1,1,1,1,1,0,1,1,1,1,0,0,0,1,1,1,1,1,0,0,1,1,1,1,1,1,1,1,1,0,0,0,1,0,0,1,0,0,0,1,0,0,0,1,0,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,1,1,1,1,1,0,0,1,1,1,1,1,0,0,0,1,0,0,0,1};
Random r=new Random();JFrame f;float x,bx=-5,by;BufferedImage bi;int[]p;int m=64,l=m*m,s,bs,ti=3;List aa=new ArrayList();int[]k=new int[3];boolean t=true,z=false;public static void main(String args[]){new A();}A() {x=32-5/2;f=new JFrame("Space");this.setFocusable(true);this.requestFocus();f.setDefaultCloseOperation(3);f.setSize(512,512);f.setLocationRelativeTo(null);f.setResizable(z);bi=new BufferedImage(m,m,1);p=((DataBufferInt)bi.getRaster().getDataBuffer()).getData();this.addKeyListener(new KeyListener(){public void keyTyped(KeyEvent e){}public void keyReleased(KeyEvent e){if(e.getKeyCode()==39)k[0]=0;if(e.getKeyCode()==37)k[1]=0;if(e.getKeyCode()==32)k[2]=0;} public void keyPressed(KeyEvent e){if(e.getKeyCode()==39)k[0]=1;if(e.getKeyCode()==37)k[1]=1;if(e.getKeyCode()==32)k[2]=1;}});f.add(this);f.setVisible(t);new Thread(this).start();}
void u(){ti-=1;if(ti<0){ti=3;aa.add(new B());}if(k[0]==1){x+=.25f*5;if(x+5>=m)x=m-5;}if(k[1]==1){x-=.25f*5;if(x<0)x=0;}if(k[2]==1&&(by+5<-15)){bx=x;by=m-10-5;}by-=.25*8;for(int i=0;i<aa.size();i++){B e=(B)aa.get(i);e.y+=.25f*8*1.14191564f;if(e.y>=64){s++;e.d=t;}else if(c(x,m-10,e.x,e.y))l();else if(c(bx,by,e.x,e.y)&&bx>-5){s++;bx=-5;e.d=t;}}for(int i=0;i<l;i++)p[i]=0;for(int i=0;i<aa.size();i++){if(((B)aa.get(i)).d)aa.remove(i);}for(int i=0;i<aa.size();i++){B e=(B)aa.get(i);ds((int)e.x,(int)e.y,as);}ds((int)x,m-10,sh); ds((int)bx,(int)by,bb);String ss=vs(s);for(int i=0;i<ss.length();i++)df(i*5,0,vi(ss.charAt(i)));ss=vs(bs);for(int i=0;i<ss.length();i++)df(32+i*5,0,vi(ss.charAt(i)));}
void l(){if(s>bs)bs=s;s=0;aa.clear();bx=-5;x=32-5/2;}
String vs(int a){return String.valueOf(a);}
int vi(char a){return Integer.parseInt(String.valueOf(a));}
boolean c(float a,float b,float c, float d){if(a+5>=c&&a<=c+5&&b+5>=d&&b<=d+5)return t;return z;}
void ds(int x,int y,byte[] d){for(int j=0;j<5;j++){if(j+y<0||j+y>=m)continue;for(int i=0;i<5;i++){if(i+x<0||i+x>=m)continue;p[(i+x)+(j+y)*m]=d[i+j*5]*0xFFFFFF;}}}
void df(int x,int y,int in){for(int j=0;j<5;j++){if(j+y<0||j+y>=m)continue;for(int i=0;i<4;i++){if(i+x<0||i+x>=m)continue;p[(i+x)+(j+y)*m]=fo[i+j*4+20*in]*0xFFFFFF;}}}
void d(){BufferStrategy bs=getBufferStrategy();if(bs==null){createBufferStrategy(3);return;}Graphics g=bs.getDrawGraphics();u();g.drawImage(bi,0,0,getWidth(),getHeight(),null);g.dispose();bs.show();}
public void run(){long n=System.nanoTime();double f=1000000000.0/30.0;double d=0;while(t){long a=System.nanoTime();d+=(a-n)/f;n=a;if(d>=1){d-=1;d();}try{Thread.sleep(2);}catch(InterruptedException e){}}}
class B{float x,y;boolean d;B(){x=r.nextInt(12)*5+1;y=-5;}}}
It's really hard to do what you did in java. Just the code for the window and keyboard input will probably consume about 512bytes. I remember there was a contest before, called java4k, although it's pretty much dead now, I tried to get some source codes of the games they used to create for that contest and I found 1 guy from who I learnt about "pack200". So using proguard + pack200 I managed to make 1.99 KB.
What is interesting is that Notch (creator of minecraft) managed to do Meg4kman in under 4KB. I don't know how he did it considering that it has enemies and 25 levels, it's pretty much a bigger project than this one. It's amazing!